All Tests 560 Flashcards
A technologist wishes to distinguish between an anti-Fy3 and anti-Fy5. Which cell will give her the best result to help differentiate between the two antibodies?
Fy(a+b+) Rhnull cell
Anti-Fy3 will react with an Rhnull cell that has Fya and/or Fyb antigens, where as an anti-Fy5 will not react with Rhnull cells of any Fy phenotype.
Which of the following techniques/reagents would be the LEAST useful in the detection of anti-Jka?
Saline room temperature
Anti-Jka is typically an IgG class antibody. IgG class antibodies do not react best at room temperature saline conditions
A D+ patient presented with a positive antibody screen and an antibody that appeared to be anti-D. The patient’s autocontrol was negative. The antibody was denatured by DTT treatment. What is the most probable identity of the antibody?
anti-LW
A patient is shown to be Ena negative. Which choice below is consistent with a phenotype for an Ena negative person?
M-N-S+s-
Ena negative individuals do not produce Glycophorin A
Which RBC phenotype below would be compatible with a patient who has an anti-G?
rr (Fya+b+), M-N-S+s+
Remember that anti-G reacts the same as a non-separable anti-C plus anti-D.
Which phenotypes will NOT react with an anti-Ku?
Ko
Ko cells will not react with anti-Ku. Anti-Ku is the antibody that is produced by Kell null individuals (Ko) and will react with the Kell antigens listed in the other choices
Which phenotype is related to resistance to malaria?
Fy(a-b-)
An anti-Ku is identified in a patient’s serum. This patient is most likely which Kell phenotype?
Ko
An individual who is Ko (or Kell null) will lack all Kell system antigens EXCEPT Kx.
A mother who is Lu(a-b+) and a father who is Lu(a+b-) have three children. Their Lutheran phenotypes are: Child 1 Lu(a+b+), Child 2 Lu(a+b+) and Child 3 Lu(a-b-) .The result of child 3 can best be described by which situation?
lulu genotype
If either of the parents had the In(Lu) gene, then they would be Lu(a-b-) as this is a dominant gene which inhibits the formation of Lutheran antigens
An individual types as M+N-S-s- Gerbich Ge: -2, 3, 4. Which statement is accurate concerning this patient?
Patient will lack Glycophorin B
A patient’s antibody screen is positive. An antibody identification is performed, and 11 of 11 cells are found weakly reactive at AGT phase, and the autocontrol is negative. The titer is 1:128. Which is most likely the cause of these results?
anti-Rg
Anti-Rg is a High Titer low Avidity antibody (PREVIOUSLY REFERRED TO AS HTLA). This means that the titer is high, but the antibody does not strongly attach to the RBCs. In addition, it is a high frequency antigen.
A patient is tested in 2012 and found to have an anti-Jka. In 2017, this same patient returns to your hospital, and his antibody screen is negative. Since his anti-Jka is not currently showing, what type of RBCs may be safely administered?
Jka negative RBCs, crossmatch compatible at AGT phase
A male child is Xga+. What parent did the child inherit the anitgen from?
child inherited the Xga antigen from his mother
A patient develops an antibody to a high frequency antigen. As part of the antibody identification, the technologist wishes to type the patient RBCs for various high frequency antigens. The patient is Caucasian. For which antigen below should the technologist test the patient?
Kpb
Look at the race of the patient. we should type him for antigens that are shown to be negative in the Caucasian population, such as Kpb
A patient is tested for a 3 cell antibody screen and all three cells are positive w+ only at the AGT phase. The screen cells are treated with ficin and patient testing is now negative with all three screen cells. Which antibody would most likely be responsible for this pattern of results?
anti-Ch
Ch antigen is destroyed by ficin treatment, and typically reacts only weakly positive at AGT.
A patient serum is tested against a panel of commercial antibody ID cells, and the following results are seen: 6 of 10 cells positive at AGT phase. The same panel of cells is treated with ficin, and retested against the patient serum. With the enzyme treated cells, 10 of 10 panel cells are negative. The antibody specificity most likely responsible for this pattern is:
anti-Fya
anti-Fya. Because the panel is positive at the AGT phase only, this is suggestive of an IgG class antibody. Next, we look at the percentage of positive cells. 60% are positive in the untreated panel. In the enzyme panel, all cells are negative, so we think of an enzyme sensitive antigen. The most reasonable choice then is the Fya antigen, so the antibody is most likely anti-Fya
A patient is tested and is found to be O Positive, with a negative antibody screen. 5 coombs phase crossmatches are performed, and one of the units is incompatible at the AGT phase. Which antibody below best fits this pattern?
anti-Kpa
Kpa is a low frequency antigen, and is not always present on screening cells.
A person has the following genes: Lua, sese, Jka, Jkb, Fya, fy. He also inherited the In(Jk) gene. What represents his phenotype?
Lu(a+b-), Jk(a-b-), Fy(a+b-)
A patient needs U negative RBCs. What is the best choice to type to find a U negative red blood cell.
U negative RBCS are usually S-s-,
Which of the following statements is true regarding McLeod phenotype?
Acanthocytes are seen on the peripheral blood smear.
What antibody exhibits high titer and low avidity behavior?
Anti-Chido
A patient’s serum reacts weakly with 16 of 16 group O panel cells only at the AHG phase of testing. No reaction was noted in the autocontrol. Further testing with ficin-treated panel cells demonstrated no reactivity at the AHG phase. What antibodies is most likely responsible for these results?
Anti-Ch
What is the titer of the Anti-K in the serum being examined in the following table:
8
What statement is TRUE of the antigens of the Lutheran blood group system and the antibodies that recognize them?
Antibodies to Lua produce a mixed field pattern of reactivity with Lua positive cells.
A woman requested prediction of the Rh genotype of her children. The phenotype results were:
Mother: dce
Husband: DEce
Paternal Grandfather: dEce
Paternal Grandmother: DcCe
Which genotype is possible for a child produced by the woman and her husband?
Ror
What is the most probable genotype (using Weiner nomenclature) of an African American bearing the following reactions: Rh 1, 2, -3, 4, 5
R1Ro
Rh antigens.Rh1 = D, Rh2 =C, Rh3 = E, Rh4 = c, Rh5 = e
Rh 1, 2, -3, 4, 5 This means that this individual has the following phenotype: D+C+E-c+e+
44% of African Americans, so we should look for a genotype that includes Ro. In this scenario, the genotype R1Ro would be more common that R1r.
What phenotypes will react with an anti-f?
- r
- Ro
What antibody is most capable of causing Hemolytic Disease of the Newborn? (non-Rh)
- K
- k
- Jsa
- Jsb
- Kpa
- Kpb
What is the amino acid sequence for the M antigen?
Serine-serine-threonine-threonine-glycine
An antibody ID panel is performed, and 10 of 10 cells are weakly positive, and the auto control is negative. The serum is titered, and the antibody has a titer of 1024. The panel cells are treated with ficin, and the panel tested again, and the results are negative. A plasma inhibition study is performed and the antibody is NOT neutralized by pooled plasma.What antibody is likely the cause?
Anti-JMH
Anti-JMH is an “HTLA-Like” antibody which reacts with most cells tested weakly, but with a high titer. The antigen is destroyed by ficin, and is NOT neutralized by pooled plasma.
When performing a neutralization using pooled plasma, you notice that both your neutralized plasma and your control plasma are negative. What is your interpretation?
The test is invalid
You have a panel that looks like anti-e with strongest reactivity on the f+ cells, but the untransfused patient is e+ and has a negative DAT. Which of the following antibodies could this possibly be?
Anti-hrs
Anti-hrs or RH19 reacts with f+ cells.
Match the following Gerbich phenotypes with the corresponding antibodies that they may produce:
Ge:-2,3,4 (Yus type)
Ge: -2,-3,4 (Ge type)
Ge: -2,-3,-4 (Leach type)
Ge:-2,3,4 (Yus type) Anti-Ge2
Ge: -2,-3,4 (Ge type) Anti-Ge2 or Anti-Ge3
Ge: -2,-3,-4 (Leach type) Anti-Ge2, Anti-Ge3 or Anti-Ge4
A specimen of RBCs give the following reactions with Rh-hr antisera:
Anti-D: +
Anti-Rhi: +
Anti-f: +
The most probable RH genotype for this patient is:
R1r
Anti-Rhi reacts with cells that have C and e on the same chromosome. Anti-f reacts with cells that have c and e on the same chromosome. Therefore, person must be Ce/ce, so R1r is the only correct choice (DCe/dce).
What is the amino acid sequence for the N antigen?
Leucine-Serine-Threonine-Threonine-Glutamic Acid
Which antigen will have a positive reaction when tested against the lectin Vicia graminea.
Anit-N
Which antigen is located on glycophorin B (GPB)?
- S
- s
- U
Which amino acid is associated with the S antigen?
Methionine
Which Gerbich antigen is destroyed by trypsin but NOT destroyed by ficin or papain?
Ge3
Which amino acid is associated with the s antigen?
Threonine
Which Gerbich phenotype is prone to RBC protein structural abnormalities such as elliptocytosis?
Ge: -2, -3, -4 (Leach)
GPC and GPD associated with the RBC membrane band 4.1 which is integral for maintaining normal RBC skeleton & shape. The Leach phenotype is completely deficient of GPC & GPD.
Which of the Duffy phenotypes is the most prevalent with African Ethnicity?
Fy(a-b-)
67% Fy(a-b-)
What Glycophorin is each phenotype lacking?
M-N-En(a)-
S-s-U-
MkMk: M-N-En(a)- S-s-U-
M-N-En(a)- Gylcophorin A
S-s-U- Glycophorin B
MkMk: M-N-En(a)- S-s-U- Gylcophorin A and B
Which antigen resides on the ACKR1 glycoprotein:
There are 5 Duffy antigens that reside on the ACKR1 glycoprotein: Fya, Fyb, Fy3, Fy5 Fy6
The antigens of Fya and Fyb differ by a single amino acid change in the N-terminus
Fya has:
Fya – glycine at position 42 or Gly42
The antigens of Fya and Fyb differ by a single amino acid change in the N-terminus
Fyb has:
Fyb – asparagine at position 42 or Asp42
A patient is diagnosed with Paroxysmal Nocturnal Hemoglobinuria (PNH), this patient cannot bind which complement regulator protein?
Decay accelerating factor (DAF or CD55)
The ____________ antigens are located on the red cell’s water transporter, aquaporin-1, encoded by AQP1 on chromosome 7p14.
Colton
If a patient has anti-hrB (RH31), which RBC units would be compatible?
R2R2
anti-hrB reacts with Ce+ or ce cells.
anti-hrB is an Rh variant with the variant at the e locus. Antibodies usually behave like anti-e, but their RBC’s type as e- positive with routine Rh typing reagents
A young child has been diagnosed with chronic granulomatous disease and has the McLeod phenotype, who is the most likely person that he inherited it from?
Mother
CGD and McLeod are linked, X-linked recessive would be passed on from the mother/carrier to the male child.
An obstetric patient has a type and screen sample submitted. The Blood Bank identifies an anti-E. the alleged father has been requested to give a sample for antigen phenotyping to determine the risk of the fetus of being E positive. The following are the antigen typing results:
50%
An eluate prepared from serum containing anti-D, anti-C and anti-G was adsorbed onto r’ red cells, they will yield:
Anti-C + Anti-G
The null phenotype for the Knops Blood Group System is:
Helgeson Phenotype
The pattern of inheritance most frequently expressed by blood group genes is:
Autosomal codominant
Cell division occurs, which results in 4 non-identical daughter cells. This type of cell division is
meiosis
An individual receives the Hepatitis B Vaccine. After receiving the third dose, the person in tested, and found to have developed anti-HBsAg. This is an example of which immunological concept?
acquired or adaptive immunity
A group O person is transfused with group A RBCs. Intravascular hemolysis is initiated via which complement pathway?
classical
An IgG class anti-Fya attaches to a Fya+ RBC. Which portion of the immunoglobulin molecule attaches to the Fya antigen?
Fab
Evaluate the pedigree and select the choice below that represents the type of inheritance pattern seen here.
autosomal recessive
A unit of blood is stored for 28 days. During this time, what changes will occur to the RBC membrane?
3 things
- the membrane will become more fragile
- the membrane deformability will decrease
- the membrane permeability will decrease
A DNA molecule has one strand with the following sequence: GTTACCG. What is the sequence of the other DNA strand (complementary strand)?
CAATGGC
Blood donor centers implemented assays in the 1990’s in which viral RNA is amplified and analyzed in order to identify donors who are at risk for transmitting viral disease. These assays use which molecular technique?
Polymerase Chain Reaction
A person has the following genotype: AB, Hh, Sese, Lele. This person’s phenotype would most likely be:
Group AB, Le(a-b+)
Which RBC below would have the Most H antigen on the RBCS?
Group O
A person’s RBCs are tested, and the following results are obtained:
The correct interpretation for this person’s results is:
Group O secretor P1 phenotype
The use of EDTA plasma prevents activation of the classical complement pathway by:
Chelating Ca ions which prevents assembly of C1
A pregnant woman’s serum contains hemolytic anti-Lea. Her husband’s RBC type is Le(a+). What is the chance that the fetus will develop immune-mediated Hemolytic Disease of the Newborn (HDN)?
0%
Lewis antigens are not expressed on infant’s RBCs at birth, so there is no risk of HDN
A group O woman and a group A man have a child. The possible ABO types that can occur from this pairing are:
A and O
A technologist decides to randomly test 100 Caucasian humans (in the USA) for ABO antigens. The results will be likely to show that the most prevalent ABO group is:
O (45%)
A specimen is tested and the results are below:
The most likely ABO type for this patient is:
group A2
A patient is typed for ABO group, and the following results are obtained:
RBC + Anti-A = O
RBC + Anti-B = O
RBC + Anti-A1 = O
RBC + Ulex europaeus = O
Serum + A1 cell = 4+
Serum + B cell = 4+
Serum + O cell = 4+
Secretor status = nonsecetor
This person is most likely a(an): ___________
Bombay phenotype
The O gene has no detectable product and is therefore termed:
amorphic
A group O individual will produce which antibodies as isoagglutinins?
anti-A, Anti-B, anti-A,B
A 5 year old male is tested for ABO group. He is found to be a group B, with an Anti-A in his serum. This child was never transfused. Why is the anti-A in his serum?
The ABO antibodies are naturally occurring antibodies
In the RBC membrane, which structures would best represent ABO antigens?
carbohydrate chains
A patient named Mike Smith is tested for type and screen, and the following results are obtained:
ABO/Rh = O Positive
Antibody Screen = Anti-P1 reacting 3+ at Immediate spin and room temperature.
This patient was transfused with blood for another patient named Mike Smith, and as a result, he received 50cc of Group A Rh positive, P1+ RBCs. The patient who was transfused had a significant immediate hemolytic transfusion reaction.
Which antibody below was MOST likely the cause of this severe, immediate, intravascular hemolytic episode?
IgM anti-A
In the classic complement cascade, how many molecules of IgG or IgM will take to activate?
- 2 IgG
- 1 IgM
“Information encoded in the DNA sequence is copied into RNA”. This statement describes which step of DNA synthesis?
transcription
The Xga blood group gene is passed on to offspring via X-linked dominant inheritance pattern.
A woman and man have a child. The woman has one copy of the gene with Xga. The man is Xga negative.
What is the percentage of offspring that could inherit the Xga gene?
50%
A patient is tested for type and screen, and the following results are obtained:
RBC + Anti-A = 3+mf
RBC + Anti-B = O
RBC + A,B = 3+ mf
Serum + A1 cell = O
Serum + B cell = 4+
Antibody Screen = negative with all cells tested
What are possible reasons for these pattern of results?
- Group A patient was transfused with group O RBCs
- Patient is an A3 subgroup
- Patient is a chimera
Which antibody specificity below is a common benign cold reacting auto-antibody?
auto-anti-I
Inheritance of the H gene codes for the production of _____________ which in turn creates the antigen structure with the terminal sugar ___________.
- L-fucosyltransferase
- L-fucose
A family study consists of 4 daughters, 4 sons, and 12 grandchildren. One son and one daughter have an inherited genetic disorder that is not present in any of the grandchildren. This is an example of:
Autosomal recessive inheritance
A trait carried on the Y chromosome will be passed from:
Fathers to 100% of sons and no daughters
A man who is genotype AO married a genotype OO woman. What is the probability that their first child will be type A?
50%
Which of the following represent the biochemical structure of the H antigen on red cells?
Cer-Glu-Gal-GlcNac-Gal-Fuc
A man phenotypes A2, Le(a+b-). His saliva shows only Lea. Which of the following best represents his genotype?
A2O, HH, Lele, sese
What is true regarding B lymphocytes?
Mature into plasma cells
The cell that regulates whether or not the immune response will occur is:
T cells
Class switching of activated B cells involves the conversion of:
lgM to lgG
CD markers T helper cells are:
CD4+
CR1 receptors on macrophages recognize:
C3b
The lgG subclasses that are most efficient in activating complement are:
lgG1, lgG3
The Fc receptor on phagocytes that has the highest affinity for binding lgG is:
FcR1
Given the following test results, what is the patient’s likely ABO type?
Ael
Initial testing at immediate spin tube testing gives the following results. What is the most probable cause of these reactions?
Group O with unexpected antibody
The following reactions were obtained on a trauma patient transferred from an outlying hospital. What is the most likely explanation for the results?
Group AB patient transfused with A RBCs
When monitoring the severity of HIV cases, patients will be tested for a ratio of T helper cells to T cytotoxic cells. In a normal individual, the ratio should be greater than 1.0 As HIV disease progresses into full blown AIDS, the ratio drops below 1.0. What cell marker would be used to measure the T Helper cells?
CD4
What is the minimum number of IgG molecules required to activate complement Protein C1?
two
Interleukin-2 (IL-2) is produced by which cells? (3)
- activated T cells
- dendritic cells
- B cells
Which of the following antibodies strongly agglutinates O cells and A2 cells, but either does not agglutinate, or only weakly agglutinates, A1 and A1B cells?
Anti-H
The detection of the actual gene products is more accurately performed by:
Protein analysis
What statements concerning the P1 antigen and Anti-P1 is true?
Antibodies to P1 demonstrate variable reactivity with all red cells expressing P1.
the P1 antigen is poorly expressed at birth, and it can take up to 7 years for a child to fully produce the P1 antigen.
A 20 year old man presents with dry cough, headache, and fever for the past 7 to 10 days. Starting 3 days ago, he noted worsening malaise and shortness of breath as well as darkening of his urine. His wife noted that his eyes were yellow. A complete blood count reveals a hematrocrit of 15% and a white cell count of 60,000/uL. His platelet count is normal. Peripheral smear examination demonstrates clumping of the red cells. His DAT is positive with polyspecific antihuman globulin reagent, negative with anti-IgG and positive with anti-C3. A chest radiograph shows patchy lower lobe infiltrates. titers for Mycoplasma pneumoniae IgM antibodies were positive. titers for IgG antibodies are negative. The patient’s forward and reverse ABO typings are discrepant. The most likely specificity of the antibody causing his anemia is:
Anti-I
The portion of the immunoglobulin molecule that determines class is the:
heavy chain
What is the correct biochemical composition of the RBC membrane?
52% protein, 40% lipid, 8% carbohydrate
Given the following test results, what is the patient’s most likely ABO type?
Saliva Study:
Patient is Group O
The transferase ______________ adds the sugar _______________ to the precursor substance to make a red cell express the A antigen.
α-3-N-acetyl-galactosaminltransferase and α-3-N-acetyl-galactosamine
Review the results of the ABO/Rh testing and what best explains the pattern of reactivity:
Patient is an A2B with anti-A1
The enzyme that is responsible for conferring H activity on the red cell membrane is:
L-fucosyltransferase
Individuals who are non-secretor, group A, Le(a+b-) would have which substance in their saliva?
Lea only
The amount of the antigen being measured that is exceeding the amount of antibody in enzyme linked immunosorbent assay can cause a technical problem called:
Hook effect
What is the correct interpretation of the results derived from the saliva inhibition study?
Group B secretor
What is aTRUE for the I/i system?
Patients with M. pneumoniae infection often develop strong cold agglutinins with I specificity
Polymerase chain reaction:
Uses DNA polymerase to replicate and amplify a specific gene sequence.
In enzyme-linked immunosorbent assay for hepatitis B surface antigen, the second antibody linked to a reporter enzyme is called:
Conjugate
If a person inherits the genes A, H, se, and Le, what is her red cell phenotype?
A, Le(a+b-)
What percentage of group A and AB individuals are A1 positive?
80%
The development of protein from RNA is referred to:
Translation
You obtain the following reactions with P system antisera:
Patient Cells with Anti-P1 = 0, Anti-P = +, Anti-Pk = 0, Anti-P1+P+Pk = +.
Based on these reactions, what is the most likely P phenotype of this patient?
P2
For the Leb antigen to be expressed, which of the following genes must be present?
Se, Le, h
What is this phenotype?
P2k
What is the correct interpretation of the results from the saliva testing for this person?
Group A secretor
The Ficin enzyme destroys certain common antigens found on red blood cells. The antigens are:
- Fya
- Fyb
- M
- N
- S
- s
- Xga
What is the frequency of the K antigen?
9%
A patient has a positive antibody screen and a positive antibody identification panel. All tested cells are positive 3+ at the AHG phase of reactivity. The autocontrol is also positive 3+ at the AHG phase. The patient has never been transfused or pregnant. Which adsorption technique would you use to complete the case?
Warm auto adsorption
You identify an RBC alloantibody in a patient. Which antibody would be eligible for antibody screens and crossmatches using the PreWarm technique?
Anti-M that does not react at the AHG phase of testing
Which glycoprotein on the platelet membrane carries the most platelet antigen?
GPIIIa
What percentage of random platelet donors are expected to be POSITIVE for the HPA-1A antigen?
98%
What is the purpose of Coombs’ control cells?
- To ensure that AHG tests with negative results are not false-negatives
- To ensure that washing removed all unbound antibody
- To ensure that AHG was not omitted or inactivated
When performing the elution procedure, the solution containing the recovered antibody is called:
The eluate
The process of removing antibody from serum by combining a serum sample with appropriate red blood cells under optimal conditions is called:
absorption
Routine pre-transfusion testing consists of all of the following except:
DAT
What is the most common use of adsorption?
Removal of autoantibody from patient serum
In what circumstance would an alloadsorption be performed?
Multiple antibodies in serum
A patient with anti-K was crossmatched with 4 units of ABO/Rh compatible, K-negative donor blood. The units were compatible in all phases of testing. After the antiglobulin phase, IgG sensitized control cells were added and a 2+ reaction was noted. The proper interpretation of this 2+ reaction is that the
cell washing was adequate.
In what test might rouleaux cause an interference?
Reverse ABO Typing
In interpreting an antibody screen, which of the following questions might be asked to decipher the class of antibody?
In what phase did the reaction occur?
Why are screening cells group O?
To prevent interference with anti-A and anti-B antibodies in patient serum.
Why is it important for screening cells to be from individuals who have a homozygous expression of antigens?
Weakly reacting antibodies may not agglutinate heterozygous cells.
How is an antibody RULED IN?
Three panel cells positive for antigen show reactivity; three panel cells negative for the antigen show no reactivity
Neonatal alloimmune thrombocytopenia is caused primarily by which antibody?
Anti-HPA-1a
The following results are obtained when testing polyagglutinable cells with a panel of lectins. Which type of polyagglutination is present?
T
An eluate prepared from serum containing anti-D, anti-C and anti-G was adsorbed onto r’ red cells, they will yield:
Anti-C + anti-G
____________ are the most common nucleotide change leading to the expression of a blood group antigen.
Single nucleotide polymorphisms
A double stranded DNA molecule consists of two single strands held together by:
hydrogen bonds
Restriction endonucleases:
cleave the DNA molecule at specific base sequences
A DNA molecule has one strand with the following sequence: GATTACA. What is the sequence of the other DNA strand?
CTAATGT
A single nucleotide substitution occurs which has no effect on the codon translation. This is an example of:
silent mutation
Recombinant proteins are:
produced in-vitro by infecting a host cell with desired DNA combined with a vector
Amplification and duplication of DNA fragments, in vitro, is a function of:
PCR
DNA purity is assessed as a ratio of optical density at:
260 nm and 280 nm
The process of RNA production from DNA is called:
Transcription
Small, circular molecules of double-stranded DNA found naturally in bacteria are termed
Plasmids
Ethidium bromide is used in PCR for:
Visualization of DNA bands using UV light
The post-zone effect is due to excess _______________?
antigens
In the solid phase technology for detecting antibodies to red cell antigens, a negative reaction would be described as:
red cells all clustered together as a button at the bottom of the well
Human somatic cells have _____ pairs of chromosomes?
23
Which hemophilias have sex-linked recessive inheritance?
hemophilia A and B
A new blood group system is defined in which the two codominant alleles are Q and P. An individual inherits two copies of the Q allele. What phenotype would this individual exhibit?
Q+P-
definition: “A silent gene that does not produce a detectable product (antigen)”
amorph
If males transmit a genetic trait to all their daughters but never to their sons, the gene could has which inheritance pattern?
sex-linked dominant
What best describes mitosis?
Genetic material is duplicated, then equally divided between two daughter cells
When a recessive trait is expressed, it means that:
Two genes carrying the trait were present
Which phenotype could NOT result from the mating of a Jk(a+b+) female and a Jk(a+b+) male?
Jk(a-b-)
In the MNSs blood group system, the expected frequency of the MS haplotype is 0.17. A given population is tested, and the observed frequency is 0.24. The difference in the frequency is a result of:
linkage disequilibrium
This pedigree is an example of which type of inheritance?
autosomal dominant
This pedigree chart is an example of what kind of inheritance?
autosomal recessive
In a pedigree, the symbol below appears. The double line in this symbol represents:
consanguineous mating
A parent has the genotype JkaJkb. Meiosis occurs and 4 gametes are produced. Two gametes have the Jka gene, and the other two have the Jkb gene. This represents which genetic concept?
segregation
The red blood cell membrane is comprised mostly of:
protein
RBCs with diminished deformability pass through the spleen and lose part of their membrane. In a peripheral blood smear, these altered RBCs would appear as:
spherocytes
The RBC membrane is freely permeable to which of the substances below?
water and anions
An immune response that is nonspecific and uniform, is called:
innate
What is the minimum number of IgG molecules required to activate Complement Protein C1?
two
How does Heparin prevents complement activation?
it inhibits the cleavage of C4
How long is complement stable for at 4C?
48 hours
The diagram below represents which antibody structure?
IgM
A patient is transfused two units of RBCs without incident. 2 years later, the patient is transfused with two units of RBCs, without any evident complications. 6 days after the transfusion, the patient appears to have a delayed hemolytic transfusion reaction due to anti-Jka. The immune system concept that best describes this incident is:
secondary immune response
In the previous question, a case was presented in which the patient developed an anti-Jka which caused a delayed hemolytic transfusion reaction. If the anti-Jka were tested, which immunoglobulin class would it most likely be?
IgG
Which of the antibodies can cross the placenta?
IgG
A patient is given IVIG (IV Immunoglobulin). This is an example of:
passive immunity
A patient produces an IgG anti-Fya. What portion of the immunoglobulin molecule is responsible for binding specifically to the Fya antigen on RBCs?
Fab fragment
The presence of bacteria, fungi, parasites, and tumor cells might activate the complement cascade via which pathway?
Alternative Pathway
When monitoring the severity of HIV cases, patients will be tested for a CD4/CD8 ratio. In a normal individual, the CD4/CD8 ratio should be greater than 1.0 As HIV disease progresses into full blown AIDS, the CD4/CD8 ratio drops below 1.0 In this scenario, the CD4 value represents a measure of:
T helper cells
Antibodies are secreted by ______ cells.
Plasma
Granulocyte Macrophage -Colony Stimulating Factor (GM-CSF) is a substance which is sometimes given to granulocyte donors in an attempt to stimulate the donor’s immune system to produce more granulocytes. GM-CSF is an example of _______?
Cytokine
A group O patient is given 50cc of group A red blood cells, and has an immediate severe hemolytic transfusion reaction. In this case, the hemolysis was most achieved via which complement pathway?
classical
Macrophages and monocytes have receptors for which portion of the IgG molecule?
Fc
When are additives such as LISS or PEG added during an antibody screening procedure?
Before 37oC incubation
In the direct (DAT) and indirect (IAT) antiglobulin techniques, false-negative reactions may result if the:
addition of AHG is delayed for 40 minutes or more after washing the serum/cell mixture
In performing an antibody screening test and/or compatibility test, the use of a patient’s specimen collected in an EDTA tube will:
prevent the detection of complement-dependent antibodies
In the direct antiglobulin test (DAT), the antiglobulin reagent is used to:
detect preexisting antibodies on erythrocytes
What is the action of AHG reagent?
Cross-links red cells that have become sensitized with antibody or complement
The proper use of IgG sensitized reagent red blood cells (check cells) will assure that:
Anti-human globulin reagent was added and was reactive
The difference between polyspecific AHG and monospecific AHG is the presence/absence of
Anti-complement
A technologist performs an antibody screen using the tube method, and reads the tubes at IS, 37C, and AHG as per the laboratory protocol. The tech adds check cells to the negative AHG reactions, and spins the tubes. The results are all negative. The most appropriate action to take is:
Repeat the entire antibody screen
How does polybrene work?
Causes aggregation of normal rbcs that can be dispersed with addition of sodium citrate / antibody coated rbcs remain agglutinated after sodium citrate addition
When performing antibody screening by solid phase testing, you note that indicator red cells are coating the sides of the well. This indicates a:
positive reaction
The lighter cell suspension is used in Gel tests is:
0.8%
According to current AABB standards, how long must recipient samples be stored?
At least 7 days after transfusion
A type and screen specimen is collected on 11-01-18 in the outpatient lab, from a 24 year old man who has no history of blood transfusions. The specimen was collected because the man is having orthopedic surgery. The type and screen was performed on 11-02-18, and the patient was typed as O Positive, with a negative antibody screen. On 11-06-18 the man is in surgery, and the surgeon calls down for two units of RBCs ASAP. According to AABB standards, what must be done in order to supply the two units of RBCs?
Crossmatch two RBCs using the routine protocol for your facility.
A specimen is received for type and crossmatch for 6 RBCs, and the following results are obtained:
Patient ABO/Rh: O Positive
Patient Antibody Screen: Negative all phases
Crossmatches: Unit 1 Compatible, Unit 2 Compatible, Unit 3 Compatible, Unit 4 Compatible, Unit 5 1+ at AHG phase, Unit 6 Compatible.
What is the most likely explanation for these results?
donor unit has a positive DAT
A request is received to crossmatch 5 units of Red Blood Cells on a man who is group AB Rh-positive.
The blood inventory shows the following:
A Rh-positive 23 units, A Rh-negative 6 units, B Rh-positive 4 units, AB Rh-positive 2 units, O Rh-positive 30 units, O Rh-negative 4 units
Assuming all the blood crossmatched is compatible, the desirable sequence of blood units that can be issued for transfusion would be:
2 units of AB-positive; 3 units of A-positive
An AGT crossmatch will detect a(an):
recipient antibody directed against antigens on the donor red cells
Which of the following might cause a false-negative antibody screen?
too heavy a cell suspension
Which of the following patients is eligible for a computer crossmatch?
Patient has no previous blood type or antibody screen results. Current antibody screen is negative. Patient types as B Rh negative. Repeat typing on the same sample is B Rh negative.
A potential transfusion recipient has a history of a previous anti-Jkb. The antibody is no longer detectable in the antibody screening test, even when enhancement techniques are used. What further action should be done before transfusion?
Give Jkb negative, crossmatch-compatible blood.
Which of the following samples is acceptable for pre-transfusion testing?
Sample labeled at the patient’s bedside. Label contains the date, patient’s full name, hospital number and the phlebotomist’s initials.
Which statement below is TRUE regarding compatibility testing for infants younger than 4 months old?
A crossmatch is not needed with the infant’s blood when unexpected antibodies are present
What is the proper interpretation of these gel test reactions:
B, Rh Positive
Bowen et al reported the first case of auto anti-Pr attributed to which vaccine?
Pneumococcal
What is the purpose of Coombs’ control cells?
- To ensure that AHG tests with negative results are not false-negatives
- To ensure that washing removed all unbound antibody
- To ensure that AHG was not omitted or inactivated
What screening cells are used primarily for testing donor units for unexpected antibodies?
Pooled
When performing the elution procedure, the solution containing the recovered antibody is called:
the eluate
In what test might rouleaux cause an interference?
Reverse ABO grouping
What is an elution?
A technique used to dissociate IgG antibodies from sensitized RBCs
A patient with a warm autoantibody has a positive DAT. The antibody screen was negative, but the eluate reacted uniformly with all normal cells and patient cells. Why was the antibody screen negative?
The warm autoantibody has bound to patient RBCs in circulation
The process of removing antibody from serum by combining a serum sample with appropriate red blood cells under optimal conditions is called:
absorption
How does LISS enhance antibody detection in the antibody screen?
Increases the rate at which antibody binds to red blood cells antigens
Which cells are employed to remove autoantibody from patient serum without removing any alloantibody from serum?
Patient red blood cells
What would be a realistic source of finding compatible units for a person with an antibody to a high-frequency antigen?
Siblings
Why is it important to match the lot number on the panel sheet with the lot number on the panel cells?
Pattern of reactions will change from lot to lot
What is high-frequency antigens that does not cause in vivo red blood cell destruction when complexed with corresponding antibody?
Cha
A person has developed an antibody to the LISS reagent. What test will not be affected by this circumstance?
DAT
How do you perform a cold antibody screens?
Patient serum is incubated with group O adult and cord red blood cells at 4°C.
Routine pre-transfusion testing consists of all of the following:
- ABO typing
- Rh typing
- an antibody screen
A positive autocontrol in antibody detection procedures is usually indicative of:
positive DAT
In interpreting an antibody screen, what question might be asked to decipher the class of antibody?
In what phase did the reaction occur?
Why is an enzyme treatment used in antibody identification?
Enzymes aid in the separation and identification of multiple antibodies and the absorption of autoantibody from patient serum.
Which of the following is a mechanism of an elution procedure?
Disruption of structural complementarity of antigen and antibody
What determines if a red blood cell antibody is clinically significant?
Shortened red blood cell survival
Neutralization of antibody is applicable to all of the following blood groups:
- P1
- Chido
- Lewis
Why are screening cells group O?
To prevent interference with anti-A and anti-B antigens in patient serum
Cold-reactive autoantibodies can be selectively removed from patient serum by adsorption with autologous red blood cells (RBCs). What other cells can be used?
Rabbit RBCs
Why is rouleaux not usually found in the AHG phase of antibody screens?
Patient serum is washed away before adding AHG.
What is the most common use of adsorption?
Removal of autoantibody from patient serum
What is a positive DAT?
In vivo sensitization of RBC with antibody
Which is the second phase of a hemagglutination reaction?
Agglutination
What test is used to confirm the efficacy of chloroquine treatment?
DAT
What antibody is associated with a mixed-field reaction?
Sda
Why is it important for screening cells to be from individuals who have a homozygous expression of antigens?
Weakly reacting antibodies may not agglutinate heterozygous cells.
How is an antibody ruled in?
Three RBC samples positive for antigen show reactivity; three RBC samples negative for the antigen show no reactivity
What can be concluded in a patient who has anti-K identified in his serum but phenotypes positive for K antigen?
Patient was recently transfused with K-positive blood and Anti-K was misidentified
What is tested in an antibody screen?
Patient serum is tested against group O reagent screening cells.
What effect does ZZAP reagent have on sensitized red blood cells?
- Removes antibody from red blood cells
- Enzyme treats red blood cells
- Increases adsorption capability of red blood cells
What is a possible explanation for a nonreactive eluate?
Positive DAT due to drugs
Why are antibodies to high-frequency antigens, such as cellano (k), rarely seen in patient samples?
Most persons are not antigenically stimulated to produce the antibody, because their red blood cells are positive for the antigen.
What might a positive antibody screen and a negative auto control indicate?
An alloantibody has been detected
When might you suspect multiple antibodies in a patient’s serum?
- Pattern of reactivity not fitting a single antibody
- Variation in phase of reactivity
- Variation in antibody reactivity strength
In what circumstance would an alloadsorption be performed?
Multiple antibodies in serum
The products of genes inherited at the ABO locus are
Transferases
The ABO genes code for the production of specific glycosyltransferases that add sugars to a basic precursor substance on the RBC. This is an important distinction!
Which is the correct interpretation of the results derived from the saliva inhibition study?
Indicator Cells
Reaction with A cell
Reaction with B Cell
Reaction with O Cell
Saliva + Anti-A
+
0
0
Saliva + Anti-B
0
0
0
Saliva + Anti-H
0
0
0
Group B secretor
Refer to the following data:
Forward Group
reaction
Reverse Group
reaction
anti-A
4+
A1 cells
neg
anti-B
neg
A2 cells
2+
anti-A1 lectin
4+
B cells
4+
Which of the following antibody screen results would you MOST LIKELY expect with the ABO discrepancy seen above?
positive with screening cells at the RT phase; autocontrol is negative
What are some statements about the P blood group system?
- The P1 antigen deteriorates with storage
- P1 Antigen expression varies among individuals
- There is an association between anti-P1+P+Pk and spontaneous abortions occurring early in pregnancy in p women.
You obtain the following reactions with P system antisera:
Patient Cells with
Anti-P1
Anti-P
Anti-Pk
Anti-P1+P+Pk
0
+
0
+
Based on these reactions, what is the most likely P phenotype of this patient?
P2
A patient inherits the following genes: Se, H, Le. Which choice below represents the correct phenotype information for this patient?
Secretor, Le(a-b+)
Oh individuals lack which one of the following transferases?
2-L-fucosyl transferase
A woman who is a group AB, has two children with a father who is group O. One child is a group B, and the other child is a group AB. Assume that the paternity of the father has been proven.
This unexpected pattern of inheritance can be explained by what rare genetic phenomenon?
Mom is a Cis AB
Patients with M. pneumoniae infection often develop strong cold agglutinins with:
I specificity
Which gene is needed to produce Lea substance in the saliva of an individual?
Le
Your institution is developing the Percutaneous Umbilical Blood Sampling (PUBS) technique. Physicians need to distinguish RBCs of fetal and maternal origin. Which method below is the best approach for discerning cellular origin?
Perform I phenotype on sample
A Le(a-b-) individual with an anti-Lea in his serum is transfused with Le(a+) red blood cells. Which statement below best describes the most likely result of this transfusion?
The patient will not have a transfusion reaction, and the DAT will be negative.
Most newborns type as which of the following Lewis phenotypes?
Le(a-b-)
At birth, most infants are lacking in any Lewis antigens
Which of the antibody is a benign autoantibody, found in many normal healthy people?
anti-I
Patient Serum is tested against:
Group O adult cell = 4+
Group A1 adult cell = O
Group A2 adult cell = 4+
Group O cord cell = O
Group A1 cord cell = O
Group A2 cord cell = O
Which antibody specificity is the most likely to cause this combination of results?
Anti-IH
An antibody panel is performed, and 9 of 11 cells are positive at IS and RT. The serum is mixed with Hydatid Cyst Fluid, and allowed to sit for 30 minutes. After that time, the panel is tested again (with the appropriate controls). The antibody panel is now totally non-reactive. The most likely explanation for these results is:
anti-P1
A patient has the genotype hh, AB. What blood group will he appear to be on the forward ABO typing?
O
A person inherits the A and H genes. Which products are coded for by those genes?
l-fucosyltransferse and n-acetylgalactosylaminase
A person has the following genotype: AO, Hh, Lele, SeSe. What phenotype will the RBCs have?
Group A, Le(a-b+)
A patient’s RBCs are tested and the following results are obtained:
What is the most likely explanation for these results?
Oh with anti-H in serum
What gene cobination will produce Lea antigen in saliva?
sese, Lele
There is no Lea gene. Only the Le gene, which can be modified by the presence of the Secretor gene Se
A patient is tested as group AB, with an AHG phase antibody screen that is negative with all three cells tested. An immediate spin crossmatch is performed with 6 different RBCs, and 4 of the 6 units are weakly incompatible at immediate spin. What is the most likely explanation for the results?
patient has anti-P1 in serum
A patient sample is tested with antisera below and the following results are obtained:
Based on these reactions, what is the most likely P phenotype of this patient?
P2
A patient is evaluated, and an anti-D is found in her serum. The antibody panel is repeated using ficin treated cells. The most likely result is____?
ficin panel shows stronger reactions
Which of the Rh antigens is the most common in both Caucasian and African American populations?
e
high frequency antigen, and is present in about 98% of the population, whether Caucasian or African American
Which Rh types will not react with the G anitgen?
r and r’’
When evaluating anti-D reagent, which cell would be the most helpful in determining that the anti-D can detect weaker expressions of D?
Dce/Ce
because of the C Trans effect
Individuals that are Goa(+), phenotype as:
Category IV partial D
What is the most probable genotype (using Weiner nomenclature) of an African American bearing the following reactions: Rh 1, 2, -3, 4, 5
R1Ro
A woman types as Rh-positive. She has an anti-c titer of 32 at AHG (this is a clinically significant titer). Her baby has a negative DAT and is not affected by hemolytic disease of the newborn. What is the father’s most likely Rh phenotype?
R1, r’ less likely Rz or ry
Refer to the following data:
Rh Genotype: Mother = cde/cde
Father = CDe/cde
These parents would most likely have a child with the genotype:
rr or R1r
When a C producing Rh gene is in trans-position (the opposite chromosome) to a D producing Rh gene, the following occurs: _______
The D expression is weakened
A patient sample is tested for type and screen, and gives the following results:
ABO/Rh: O Positive
Antibody Screen = Negative
Two units of type specific RBCs are crossmatched through the AGT phase, which is the policy of the blood bank. One unit is 2+ incompatible at AGT phase. The incompatible unit has a negative DAT.
Which Rh antibody is most likely responsible for this type of scenario?
anti-Cw
A 40 year old Group O Negative male, with no history of transfusion has a hemoglobin of 6.0. The physician decides to transfuse 2 units of RBCs, but no Rh negative units are available. Two units of O Positive RBCS are transfused to this patient. The most likely result will be: ________
no transfusion reaction, and no positive DAT
If you remember from the immunology section, IgG antibodies are not formed until the secondary immune response.
A first time blood donor is phenotyped for Rh antigens, and the following results are obtained.
Anti-D = O
Anti-C = O
Anti-E = O
Anti-c = O
Anti-e = O
What is the most probable cause for these results? (assume that the serology was done correctly, and that the QC was acceptable)
Rh null
A patient specimen is evaluated, and an anti-Rh 29 is identified in the serum. Which cell would test NEGATIVE with this patient specimen?
Rh null
A patient typed A Rh positive with strong reactions with the Rh typing sera. The patient had a strong apparent anti-D in his serum and the autocontrol was negative. The antibody was non- reactive after the cells were treated with both DTT and Pronase. The most likely specificity of this antibody is ____?
Anti-Lw(a)
A mother has an anti-Lw(a) which reacts 2+ at AHG phase. It is suspected that her fetus is Lwa+. What is the most likely result in this situation?
baby will not suffer from Hemolytic Disease of the Newborn
The Rhnull phenotype can be a result of 2 different mechanisms. Which is the most common?
regulator__
If a patient has anti-hrB (RH31), which RBC units would be compatible?
R2R2 or r” less likely RZ or ry
If a patient has anti-hrB, he is producing a variant of anti-e so you must avoid giving the patient e antigen positive blood.
What genotypes are consistent with f antigen expression?
r or Ro
Less D antigen is expressed when the C antigen is present, a phenomenon called the
Ceppellini Effect
Of the following MNS system antibodies, which one is usually IgM isotype and clinically insignificant?
Anti-N
A technologist performs an antibody ID panel at room temperature, and gets weak results which do not seem to match any specific antibody pattern or reactivity. She lowers the pH of the test system, repeats the antibody screen, and sees a definite pattern or reactivity. The antibody she most likely detected is:
Anti-M
A person with the genotype MgN will type serologically as:
M-N+
A propositus is Ena negative. Based on the following typing results on his parents, what is his most likely phenotype?
Father: M+N-S+s+
Mother: M-N+S+s+
M-N-S+s+
Anti-N is rarer than anti-M because:
The ‘N’ antigen on GPB prevents N negative individuals from recognizing N as a foreign antigen
The 26 terminal amino acids of Glycophorin B (GPB) are identical to the sequence of GPA(N) (glycophorinA N antigen).
What MN phenotype has the highest fequency in the caucasian population?
M+N+
About 49% of Caucasians and 49% of African Americans have this phenotype.
Are MNSs anitgens well developed at birth?
yes
Which clinical condition is associated with the Leach phenotype? (Gerbich System)
Hereditary elliptocytosis
The Gerbich blood group is composed of which high incidence antigens?
Ge2, Ge3, Ge4
The Gerbich phenotype YUS is written as: Ge: -2, 3, 4. What is the correct combination of serologic reactions that corresponds to this phenotype?
Ge2- Ge3+ Ge4+
When writing the Gerbich phenotype, a negative sign (-) is inserted before the antigen that is lacking. Therefore, in the YUS phenotype, Ge-2, 3, 4 means that the person is negative for Ge2 antigen only (or Ge2- Ge3+ Ge4+)
An individual produces an anti-Ge2, and anti-Ge3 in his serum. His red blood cells type as: Ge-2, -3, 4, and the Kell system antigens K, k, and Kpb all give weakly positive reactions. The most likely Gerbich phenotype for this patient is:
Gerbich
These individuals are capable of producing anti-Ge2 and anti-Ge3, and have weakened expression of Kell antigens.
A patient with an anti-U requires transfusion. Blood from donors of which ethnic background are most likely to lack the U antigen?
African Black
The vicia graminea lectin is used to detect specificity for which MNSs antigen?
N
An individual’s genotype is MgS/Mgs. His RBCs would phenotype as:
M-N-S+s+
An individual is suspected of having the Dantu antigen, but the laboratory does not have any anti-Dantu. The technologist can screen for the Dantu antigen if she treats the RBCs with _________ and then types the treated RBCs with Vicia Graminea.
Ficin
Remember that treating the RBCs with ficin, will denature the N antigen, but not affect the Dantu or Sta antigens. If you ficin treat the RBCs, and get rid of the N antigen, then you can type the treated RBCs with Vicia Graminea to detect the DANTU antigen.
An individual’s RBC phenotype is: M-N+S-s+. From this we know for certain that his MNSs Genotype is:
Can’t determine the genotype for certain
What patients is MOST likely to produce an anti-U?
S-s- female who has a history of previous transfusions
A patient is suspected of having an anti-Wb. Which scenario below describes how you would best detect this antibody?
Anti-Wb is usually detected by testing the patient serum with a panel of RBCs positive for various Low frequency antigens
Anti-Wb is usually detected by testing the patient serum with a panel of RBCs positive for various Low frequency antigens:
- Glycophorin A (GPA)
- Glycophorin B (GPB)
- Glycophorin C (GPC)
- Glycophorin D (GPD)
- Glycophorin A (GPA) carries M, N, Ena
- Glycophorin B (GPB) carries S, s, U
- Glycophorin C (GPC) carries Ge3 and Ge4
- Glycophorin D (GPD) carries Ge 2 and Ge3
There is an association between the McLeod phenotype (Kell Blood Group System) and what disease?
Chronic Granulomatous Disease
A patient is tested, and found to have anti-K2 in her serum. What pattern of reactivity would you expect to see in the antibody ID panel tests?
positive reactions at AGT phase only with 10 of 11 cells tested
Which of the Js and Kp anitgens are more common?
- Kpb
- Jsb
An individual types as follows: K-k-Kpa-Kpb-
What antibodies is this patient most likely to produce?
Anti-Ku
The Duffy glycoprotein is the receptor for which parasite?
Plasmodium vivax
Anti-Fy3 and anti-Fy5 can be distinguished by testing the serum against a cell that is:
Rh null
The incidence of Fy(a-b-) among African Americans is:
67%
As we all know, enzymes can denature certain RBC antigens. Which Duffy antigens that are destroyed by ficin treatment?
Fya and Fyb antigens
Which of the phenotypes of Kidd is resistant to lysis by 2M urea?
Jk(a-b-)
Which statement below best describes anti-Jk3?
appears as an inseparable anti-JkaJkb
An individual is Lu(a-b-), has normal expression of all other RBC antigens, and produces an anti-Lu3. This individual is most likely:
lulu
The In(Lu) individual may also type as Lu(a-b-), or will have extremely weak Lutheran typings. In addition, the R1, i, Inb, AnWj antigens are affected, and this individual typically does NOT make anti-Lu3
An individual types as Jk(a-b-). This individual is MOST likely to be:
JkJk
JkJk genotype is more common than the In(Jk)
A prenatal antibody screen reveals an anti-Lua in the serum. Which statement best describes the risk to the fetus?
The fetus will most likely not progress to have Hemolytic Disease of the Newborn
You suspect that you have an anti-Jkb antibody in the serum, and wish to enhance the reactivity. Which method can you use to enhance the reaction strength of the anti-Jkb in the tube method? (3)
- ficin treat the panel cells
- enhance the serum to cell ratio
- use Polyethylene Glycol (PEG) as the enhancement media
A person has the genotype LuaLua. He inherits an In(Lu) gene also. What is his Lutheran phenotype going to be?
Lu(a-b-)
In(LU) gene will suppress the expression of the Lutheran antigens, regardless of the Lutheran genes that are inherited. This gene is inherited independently from the Lutheran genes.
All of the following statements are true of anti-Jka (3)
- It is often implicated in delayed hemolytic transfusion reactions (DHTR)
- serologic reactivity is sometimes dependent on the use of polyspecific AHS
- activity may decrease in strength during storage
Some examples of anti-Jka are not detected unless you use a polyspecific AHG reagent. Remember that Kidd antibodies are very effective at binding complement. In some cases, the kidd antibodies can be attached to the cell, but the antibody molecules have bound complements from the serum and the Fc portion of the molecule is blocked, and can’t be detected by the anti-IgG reagent. Use of a polyspecific reagent picks up the complement coating the cells, and allows us to detect the anti-Jka.
A patient has a positive antibody screen in which 9 of 10 cells are 1+ positive at the IS phase and the autocontrol is negative. The entire panel is negative at the AGT phase. The technologist performs a test in which she mixes patient serum with guinea pig urine (something we all routinely stock in the blood bank fridge!) and repeats the panel. The panel is now completely negative. Which antibody specificity is most likely to cause this pattern of results?
Anti-Sda
A patient presents to the emergency room, and is drawn for type and screen. The patient is transfused with 2 units of RBCs and 2 units of FFP before the pretransfusion testing is completed. The antibody screen on the initial blood specimen is positive, and the two units that were transfused are incompatible with this specimen. Another sample was drawn on the patient following the transfusion and the antibody screen is now negative and the units are compatible with this specimen. What is the most likely explanation?
patient has anti-Ch
The Inab phenotype in the Cromer system is considered the null phenotype. These RBCs lack all cromer antigens because of the following reason?
Inab cells have no Decay Accelerating Factor (DAF)
An Xga positive male marries an Xga negative female. The couple have 4 children: 3 boys and 1 girl. Applying the laws of genetics, we can confidently say:
- 0% of the sons will have the Xga antigen
- 100% of females will have the Xga antigen
- 100% of the females will be heterozygous for Xga
A patient has an antibody ID panel in which 10 of 10 cells are weak positive at the AGT phase and the autocontrol is negative. The technologist performs an enzyme panel, which is negative with all cells tested. The technologist performs a titer, and the result is 1:256. Which test would be the best next step to try to further identify the antibody?
Perform inhibition studies using pooled human plasma
An antigen has the following characteristics:
- High incidence (more than 99.9% of population)
- Antigen is resistant to enzyme treatment and 0.2M urea
- The antigen negative phenotype has only been reported in Black individuals (African American, and African populations)
Ata
Antibody identification is performed on the serum of a previously transfused patient. The 11 cell antibody ID panel revealed 2 weakly positive AGT reactions. The autocontrol was negative. 5 units of RBC were crossmatched, and 4 were compatible. One RBC was weakly positive at the AGT phase. A DAT was performed on the unit, and it was negative. Which antibody specificity is the MOST likely explanation for these reactions?
Anti-Bga
You are working the PM shift at a transfusion service. A patient specimen is tested, and is proven to have an anti-Kna. 2 units of RBCs are requested for surgery in the morning. You crossmatch 6 RBCs and all of them are weakly incompatible. Which choice represents the best strategy for selecting RBCs for transfusion?
Select the two units that are the least incompatible
Anti-Kna (Knops A) is NOT a clinically significant antibody. Therefore, you do not need to have antigen negative RBCs for transfusion. Also, only about 1% of the population in the USA is Kna-.
It has been said that the Dia antigen can be used as an anthropogenic marker. This is true because the Dia antigen is found almost exclusively in the ___________ population.
Native North and South American
A patient is suspected of having an anti-Wb. Which scenario describes how you would best detect this antibody?
Anti-Wb is usually detected by testing the patient serum with a panel of RBCs positive for various Low frequency antigens
Wb is a low frequency antigen in the Gerbich system. Because it is a LOW frequency antigen, it is not likely to be present on the commercial antibody screening cells or a commercial panel.
A patient develops an antibody to a high frequency antigen. As part of the antibody identification, the technologist wishes to type the patient RBCs for various high frequency antigens. The patient is Caucasian. For which antigen should the technologist test the patient?
Kpb
A patient’s serum reacts microscopically to 1+ with 8 of 11 cells tested with no apparent specificity. The antibody was non-reactive with the same panel of cells that were ficin treated. This antibody was titered and tested with one of the incompatible cells. The titer was 64 with a score of 15. Which specificities should be considered?
Anti-Ch and anti-JMH
A patient’s serum reacted with cells I and II of a three cell screen and three group O, Rh negative cord cells. When the cells were DTT treated, the serum was negative. The most likely specificity is:
Anti-LW
A Native American woman (group A, Rh positive delivered a group O, Rh positive) infant. The baby was noted to be jaundiced 6 hours after birth and had a 3+ DAT. The mother’s antibody screen had been negative before delivery, and an eluate prepared from the infant’s cells was also non-reactive with a routine antibody identification panel and A1 and B cells. Which cells should be tested to possibly assist in identification?
Dia
This antibody typically causes red cells to exhibit a refractile shiny appearance and mixed field reactions at AHG, and can be neutralized by most human urine.
Sda
What solution can denature Bennett-Goodspeed antigens?
Chloroquine diphosphate
Which of the following is true regarding the Diego antigens?
They are not destroyed by enzymes
Which of the following is true regarding the Xg blood group system?
Antibodies react in the AHG phase
Are Knops antigens resistant to ficin?
Are Knops antigens clinically significant?
Where are the Knops antigens located?
- Antigens are resistant to ficin
- Antibodies are not clinically significant
- Antigens are located on a complement glycoprotein
What class of antibodies are directed against the Colton system?
IgG
What is unique about the Chido/Rogers system?
Antibodies are neutralized by antigen positive plasma
How is anti-SC3 produced in patients?
Produced in patients with Scianna null phenotype
What enzymes destroy Ina and Inb?
- Papain
- Ficin
- DTT
Which Gerbich phenotype produces anti-Ge2?
Ge:-2,3,4 (Yus)
Are John Milton Hagen (JMH) antigens destroyed by proteolytic enzymes
Yes
Which glycoprotein on the platelet membrane carries the most platelet antigens?
GPIIIa
What platelet antibody specificity is responsible for at least 50% of NAIT cases?
Anti-HPA-1a
Which types of Polyaggultination are positive with Arachis hypogaea?
- T
- Th
- Tk
Which types of Polyaggultination are positive with Dolichos biflorus?
- Tn
- CAD
Which types of Polyaggultination are positive with Glycine max (soja)?
- T
- Tn
- CAD
Which types of Polyaggultination are positive with Salvia sclarea?
- Tn
Which types of Polyaggultination are positive with Salvia horminum?
- Tn
- CAD
Which types of Polyaggultination are positive with Cord Serum?
- All Negative
Which types of Polyaggultination are positive with Griffonia simplicifolia GSII?
- Tk
Which of the polyagglutinable types are from a Microbial origin?
- Th
- Tk
- T
Which of the polyagglutinable types are from a inherited origin?
- CAD
Which of the polyagglutinable types are from a mutation origin?
- Tn
Which of the following would be the best source of platelets for transfusion in the case of alloimmune neonatal thrombocytopenia?
Mother
What percentage of random platelet donors are expected to be NEGATIVE for the HPA-1a antigen?
2%
Which one of the polyagglutinable states is transient?
T
It is usually associated with septicemia, gastrointestinal lesions or wound infections.
Tk polyagglutination may lead to decreased expression of certain antigens. Which represents the correct combination of antigens that is decreased?
ABH, Ii, Lewis, and P1 antigens
Which of the statements below is TRUE for anti-HPA-1a?
- It can cause NAIT in the first pregnancy
- It is incompatible with approximately 98% of the random population in the USA
- It can cause post transfusion purpura in a transfused patient
In the degree of matching for HLA-matched platelets, there is 1 mismatched antigen present. What match grade is this?
C
Panel data concludes that the patient has an anti-K1. Anti-c has not been ruled out. Which cells should ideally be used to rule out anti-c?
K- k+ C- c+
An antibody identification study is performed, and the results are to be evaluated. What questions should be investigated in order to properly evaluate the results. (5)
- Is the autocontrol positive or negative?
- In what phase(s) and at what strength(s) did the positive reactions occur?
- What antibodies can be ruled out or eliminated as possibilities?
- Do the serum reactions match any of the remaining specificities
- Is there sufficient evidence to prove the suspected antibody?
A panel of enzyme treated RBCs is tested. Which antibodies could not be ruled out using this enzyme treated panel?
Anti-Fya, Anti-M, Anti-N
Look at the antibody screen results below:
AHG CC
Screen Cell I O 2+
Screen Cell II O 2+
Screen Cell III O 2+
Autocontrol 2+ N/A
What is the most likely explanation for these results?
Patient has an autoantibody
Review the antibody screen results below.
What is the most likely explanation for these results?
An IgM alloantibody is present
Treatment of Neuraminidase to reagent red blood cells will ________ the Pr antigen and ________ the T antigen
destroy/expose
What is used to pretreat RBC’s with positive DAT to enhance warm autoadsorption
ZZAP
What enzyme inactivates cold IgM antibodies interferring with warm IgG antibody
DDT
What is used to treat RBCs with a positive DAT to dissociate antibody from the RBC membrane so that the RBCs can be typed
Chloroquine diphosphate
What is used to differnetiate rouleaux from true agglutination?
Saline replacement
What is it called when anti-Ch nad anti-Rg can be neutralized with the plasma if antigen positive individuals?
Inhibition
In the direct antiglobulin test (DAT), the antiglobulin reagent is used to:
detect preexisting antibodies on erythrocytes
What is the most appropriate control for a positive direct antiglobulin test?
patient cells and saline
You have a serum sample which has anti-e, anti-Fya, and anti-Jka. The goal is to remove the anti-Fya specificity from the serum sample. Which cell is the best choice to use as an adsorbing cell?
e-Fya+Jka-
A patient is tested, and the following results are obtained:
ABO/Rh: O Positive
Antibody Screen: SCI = 2+ AGT phase, SCII = 2+ AGT phase, SCIII = 2+ AGT phase, Auto = 2+ AGT phase
which type of eluate is the best choice for the next phase of testing?
Cold-Acid
An example of the cold acid is the ELUKIT, a commercially made eluate kit.
A 56-year-old female with cold hemagglutinin disease has a positive direct antiglobulin test (DAT). When the DAT is repeated using monospecific antiglobulin sera, what is most likely to be detected?
C3d
A patient who has not been transfused within the past three months has the following pre-transfusion results:
ABO/Rh: O Positive
The antibody screen was positive, and so an antibody ID panel was tested, and the results are all cells and autocontrol are positive. What test should be performed next?
Autoadsorption
A patient is found to have a broad spectrum cold autoantibody. What techniques would be helpful in diminishing the effects from the cold auto within the testing system?
- pre-warmed techniques
- use of anti-IgG monospecific AHG reagent
- cold adsorption (allo or auto)
A patient is on high levels of penicillin delivered via IV line. He has a strongly positive DAT. The serum antibody screen shows negative reactions with SCI, SCII, and SCIII. The autocontrol is positive at the AGT phase. The citric acid elution is negative when tested with screen cells and ABO reverse cells. What additional cells could be tested with the serum and eluate in an attempt to identify the cause of the positive DAT?
Drug coated cells
Anti-ceftriaxone antibodies are known to cause intravascular hemolysis via which drug-anti-drug mechanism?
membrane modification
A patient has been on large doses of alpha-methyldopa (trade name aldomet) for an extended period of time. The patient presents with the following pre-transfusion testing results:
ABO= B Pos
SCI =2+
SCII = 2+
SCIII = 2+
Auto = 2+
Hemoglobin = 7.0 gm/dl
This scenario represents a drug induced hemolytic anemia due to which mechanism?
warm autoantibody production
A patient has a compensated hemolytic anemia due to Cephalosporin, acting according to the membrane modification mechanism. This patient’s DAT results are below:
Poly = 2+
IgG = 2+
C3 = 2+
Control = 0
An eluate is performed and tested against panel cells, ABO reverse cells, and cephalosporin coated cells. What is the most likely pattern of reactivity that we will see with the eluate?
All cells are negative
