Blood Bank Exam 5 Flashcards
1
Q
Icterus gravis
A
Jaundice
2
Q
Erythroblastosis fetalis
A
Immature RBCs in circulation
3
Q
Hydrops fetalis
A
Generalized term for edema in fetus/neonates
4
Q
What are the various names of HDFN?
A
Hydrops fetalis, Icterus gravis, Erythroblastosis fetalis, Anemia of the newborn
5
Q
What is the most severe form of HDFN? Least severe?
A
Rh most severe
ABO lease severe
6
Q
Three main causes of HDFN
A
Rh, ABO, and other RBC antigens
7
Q
What are the four conditions that must be met for HDFN to occur?
A
- Mother must be exposed to foreign antigen from pregnancy
- Exposure to foreign antigen results in immunization and antibody production
- Antibody has to have the ability to cross the placenta (IgG) in sufficient concentrations to cause rbc destruction
- Infant must possess the corresponding antigen and it must be well developed
8
Q
Placental function
A
Exchanges oxygen, nutrients, waste products; serves as a barrier between fetal and maternal circulation
9
Q
Can Rh/other non-ABO antibodies cause HDFN in first pregnancy?
A
No, this is the stimulating pregnancy. Only ABO HDFN can occur in first pregnancy but can be mild.
10
Q
How can ABO HDFN occur in first pregnancy?
A
O mother giving birth to an A or B child
11
Q
Which pregnancy can Rh/Non-ABO antibodies cause HDFN?
A
Only the second pregnancy because IgG antibody can now cross the placenta.
12
Q
What are symptoms of HDFN?
A
Anemia, Increased bilirubin leading to kernicterus, Low hemoglobin
13
Q
What is accumulation of bilirubin in the central nervous system called? What can it lead to? When would this occur?
A
Kernicterus –> can lead to deafness, mental retardation, death, heart failure. This would occur after birth.
14
Q
Why does bilirubin increase during HDFN?
A
Sensitized fetal RBCs are destroyed in the liver causing increase in bilirubin, fetus cannot conjugate bilirubin due to lack of glucuronyl transferase enzyme
15
Q
What are the “other” types of HDFN? Why?
A
Anti-K, Anti-Duffy, Anti-Kidd, since these are IgG, able to cross the placenta, and well developed at birth
16
Q
What type of HDFN can occur in any pregnancy?
A
ABO (Group O mothers with Group A or B infants)
17
Q
S&S of infant with ABO HDFN
A
Elevated ESR
Increased osmotic fragility
Increased spherocytes
Mild to high bilirubin
18
Q
ABO HDFN DAT
A
Usually weakly positive or negative
19
Q
What are some types of prenatal testing before birthing process to assess HDFN?
A
ABO, Rh, Weak D, Antibody screen, Antibody titrations
20
Q
How to determine antibody titer?
A
Last positive result is your titer
21
Q
1st titer vs 2nd titer for prenatal antibody testing
A
1st titer is an estimate of maternal antibody concentration
2nd titer is run in parallel with 1st specimen; any change >2 steps is a significant increase
22
Q
Significant titers
A
16, 32 or higher
23
Q
How to test bilirubin in baby
A
Delta A450 test on Liley Graph
24
Q
What is the X and Y axis on a Liley Graph?
A
X axis = Weeks Gestation
Y axis = Delta OD450
25
What do the zones mean on a Liley Graph? Where are they located?
Zone 1 (bottom third) means the baby is not affected
Zone 2 (middle) means the baby is affected, continue to monitor
Zone 3 (Top third) means the baby has life threatening anemia, consider induction of labor
26
Percutaneous umbilical blood samples (PUBS) aka? What can it perform?
Cordocentesis; Can perform hemoglobin, hematocrit, bilirubin, reticulocyte, DAT
27
What are FDA AABB blood requirements for IUT?
Fresh blood <5 days old
CMV negative (leukoreduced)
Hemoglobin S negative
Irradiated
O Neg pRBC and AB FFP
28
What are 2 ways to perform an IUT?
1. Transfuse the fetus directly through abdominal wall into peritoneum
2. Intravascular IUT
29
What 5 criteria is cord blood testing required for? (not all of them needed, just 1 is enough to perform cord bloods on)
1. Infants with Rh negative mothers
2. Infants from Group O mothers
3. Infants in the NICU
4. Infants born from mothers with clinically significant antibodies
5. Infants born from mothers with no prenatal historu
30
What tests are done on cord bloods?
ABO, Rh, Weak D on Rh negs, DAT, Elution if DAT is pos
31
What can cause a false positive with cord blood testing?
Wharton's Jelly, In vivo sensitization
32
What is the blocking phenomenon?
All D sites on baby's D cells are blocked by maternal anti-D causing a false negative (D neg when they are actually D pos)
33
What is normal cord blood hemoglobin? What value indicates severe anemia?
14-20 g/dL
<8 = severe anemia
34
What is normal cord bilirubin?
1-3 mg/dL
35
What is abnormal cord bilirubin? When should a fetal IUT occur? What indicates kernicterus?
Greater than 3.
Fetal IUT should occur if bilirubin is 16 mg/dL.
18-20 mg/dL or more = kernicterus
36
What is the single most important serological test in the diagnosis of HDFN after birth?
DAT
37
What can cord hemoglobin help us to determine?
Anemia and red cell destruction
38
What can cord bilirubin help us to determine?
The need for exchange transfusion (IUT) and presence of kernicterus
39
Neonatal treatments for HDFN
Phototherapy (UV light)
Exchange Transfusion
IVIG
40
How to determine the selection of blood for exchange? (ABO)
Always give O blood (unless mom is A and baby is A or mom is B and baby is B, then give type specific)
Always match baby for FFP
41
How to determine the selection of blood for exchange (Rh)?
If mom and baby are positive, give positive.
If mom and baby are negative, give negative.
If mom is pos and baby is neg, give neg.
If mom is neg and baby is pos: give neg if infant has HDFN due to maternal anti D and give pos if ABO HDFN is suspected or other AB causing HDFN other than anti-D
42
Standard dose of RhoGAM
300 micrograms intramuscularly
43
When is RhoGAM administered?
72 hours post delivery
44
Candidates for the administration of RhoGAM
Rh negative women with Rh positive infants that are non-immunized (do not already have anti-D) OR
After invasive procedures (miscarriages, abortions, ectopic pregnancies, amniocentesis
45
Non-candidates for the administration of RhoGAM
Rh negative moms with Rh negative infants
Rh negative moms who already have a real anti-D
Rh positive mothers
46
How much blood will a 300ug dose of RhoGAM protect against?
30 mL of whole blood or 15mL of red cells of fetal blood in moms circulation
47
What is the fetal screen test? What is a positive result?
Qualitative test to detect Rh positive cells in the fetus; positive if rosette formations/clumping is/are present
48
What do you do next if the fetal screen is positive?
Kleihauer-Betke Test
49
What is the Kleihauer-Betke test? What is a positive result?
Quantitative test to detect fetal hemoglobin in mom's circulation; hot pink cells is a positive result and must quantify by counting 2000 cells
50
If a DAT is positive on a cord blood, what could this mean and what additional testing should be performed?
In vivo sensitization (HDFN). Elution should then be performed.
51
If you have a group O- mother, what are the next steps?
Cord blood testing; if baby is Rh +, must do fetal screening, then KB testing, then RhoGAM if those tests are positive
52
What is the calculation for how many vials of RhoGAM is needed to give to a mother?
Count 2000 cells and calculate the # of fetal cells (# counted/2000).
Calculate volume of FMH by taking # fetal cells/5000
To determine dose of RHiG: volume of FMH/30
Round up if above 0.5 and add a safety vial
(Ex. if dose = 3.77, mother would get 5 vials of RHiG)
53
What is HLA?
Human Leukocyte Antigen
54
Where is the Human MHC found?
Short arm of chromosome 6 (p arm)
55
What are the three distinct gene regions found on chromosome 6 and what do they contain?
Class 1: A, B, C glycoproteins
Class 2: DP, DR, DQ glycoproteins
Class 3: complement and TNF
56
What is in the 1st field of HLA?
Protein/allele groups
57
What is in the 2nd field of HLA?
Specific allele variants
58
What is in the 3rd field of HLA?
Synonymous DNA substitutions in coding (exons)
59
What is in the 4th field of HLA?
Non-coding region differences (Introns and UTRs)
60
How are HLA antigens inherited? What phenomenon also exists?
Codominantly (one haplotype from mom, one haplotype from dad); linkage disequilibrium also exists
61
Which class of HLA alleles is more common?
Class I (A, B, C glycoproteins)
62
What cells have HLA class I?
All nucleated cells (not mature RBC)
63
What cells have HLA class II?
B cells, macrophage, dendritic cells (Antigen Presenting Cells)
64
What are the HLA class I loci?
A, B, C
65
What are the HLA class II loci?
DR, DP, DQ
66
What is the source of antigens being screened by HLA class I?
Endogenous; inside of the cells (intracellular) ex. cancer, viruses
67
What is the source of antigens being screened by HLA class II?
Exogenous; outside of the cell (foreign things that are extracellular such as bacteria or fungus)
68
What is the structure of HLA Class I?
3 alpha chains covalently attached to Beta-2-microglobulin (antigen binding site between alpha 1 and alpha 2)
69
What is the structure of HLA Class II?
2 alpha and 2 beta chains (antigen binding site between alpha 1 and beta 1)
70
What type of T cells does HLA class I interact with?
CD8+ and NK cells
71
What type of T cells does HLA Class II interact with?
CD4+ cells
72
What is occurring in the CDC assay?
Testing for HLA; donor lymphocytes are mixed with patient plasma and complement and AHG are added; if HLA antibodies are present complement may lyse cells
73
What is engraftment monitoring for?
Monitoring signs for rejection and GvHD - easy way to assess for chimerism within blood
74
What is chimerism?
Two sets of DNA; when both donor and patient T cells are present in bone marrow; assessed using Engraftment Monitoring
75
GvHD in HLA
Can result from solid organ and BM transplantation --> organ rejection where graft recognizes host immune system as foreign and destroys it
76
HvGD in HLA
Can result from organ or BM transplant --> host immune system recognizes graft as foreign and destroys it (better than GvHD)
77
What is GvHD/HvGD based upon?
T mediated responses (Class I)
NK mediated responses (Class I)
Antibody mediated responses (Class II)
Complement activation
78
Symptoms of Acute GvHD
Endothelial damage and cell death to skin, liver, and GI tract -- rash, jaundice, diarrhea, hemorrhage
79
GvHD treatment and prevention
HLA testing for best matches
Intense immunosuppression and steroids
80
Direct vs indirect allorecognition of donor tissue
Direct more severe - acute graft rejection
Indirect weak - chronic graft rejection
81
What are the genetic markers analyzed for paternity testing?
RBC antigens, HLA antigens, Enzymes, Serum proteins
82
1st order of exclusion/direct exclusion for paternity testing
A characteristic present in the child that is absent from the mother and the alleged father
83
2nd order of exclusion/indirect exclusion for paternity testing
A characteristic absent in the child that should be transmitted by alleged father given his observed phenotype
84
What drug is associated with Drug Adsorption hemolytic anemia?
Penicillin most common; also Cephalosporin, Erythromycin, and Tetracycline
85
What lab results are associated with Drug Adsorption hemolytic anemia? (DAT w/ polyspecific, DAT w/ IgG, DAT w/ C3)
pos DAT w/ polyspecific
pos DAT w/ IgG
neg DAT w/ C3
86
What is the mechanism of Drug Adsorption hemolytic anemia?
Drug acts as a hapten (cannot be immunogenic without a protein carrier)--> extravascular hemolysis
87
What drug is associated with Immune Complex hemolytic anemia?
Phenacetin, quinine, quinidine, sulfonamides, acetaminophen
88
What lab results are associated with Immune Complex hemolytic anemia? (DAT w/ polyspecific, DAT w/ IgG, DAT w/ C3)
pos DAT w/ polyspecific
neg DAT w/ IgG
pos DAT w/ C3
89
What is the mechanism of Immune Complex hemolytic anemia?
Drug and antibody combine to form a complex and causes intravascular hemolysis
90
What drug is associated with Membrane Modification hemolytic anemia?
Cephalosporins, Keflex, Keflin
91
What lab results are associated with Membrane Modification hemolytic anemia? (DAT w/ IgG, DAT w/ C3)
pos DAT with IgG
pos DAT with C3
92
What is the mechanism of Membrane Modification hemolytic anemia?
non-immunologic action; no hemolysis
93
What drug is associated with Unknown Mechanism hemolytic anemia?
Aldomet, L-DOPA, Ibuprofen
94
What lab results are associated with Unknown Mechanism hemolytic anemia?(DAT w/ polyspecific, DAT w/ IgG, DAT w/ C3)
pos DAT with polyspecific
pos DAT with IgG
rarely pos DAT with C3
95
What lab values are suggestive of intravascular hemolysis?
neg DAT with IgG
pos DAT with C3
Eluate Negative
96
What lab values are suggestive of extravascular hemolysis?
pos DAT with IgG
neg DAT with C3
Eluate negative because RBCs destroyed `
97
What is drug-induced hemolytic anemia?
Certain drugs inducing the formation of antibodies that can react against the drug itself or against red cell antigens (POSITIVE DAT)
98
Adsorption vs Elutions
Adsorptions: removal of antibodies from serum
Elution: removal of antibodies from cells
99
What lab findings correlate to immune hemolytic anemia?
Decreased hgb
Decreased hct
Increased retics
Increased bilirubin
Decreased haptoglobin
Increased serum LDH
100
What is the most common immune hemolytic anemia?
Warm autoimmune hemolytic anemia
101
What is the most common warm autoimmune hemolytic anemia?
Anti-e
102
What is the most common cold hemaglutinin disease?
Anti-I
103
Lab results for Cold Hemaglutinin Disease (Eluate, DAT w polyspecific, IgG, and C3)
- Eluate
pos DAT w/ polyspecific
neg DAT IgG
neg DAT C3
104
Eluate results for Warm Autoimmune Hemolytic Anemia
Positive if red cells are coated with both IgG and C3 or just IgG
105
Special Features of Paroxysmal Cold Hemoglobinuria (PCH)
Seen primarily in children; Positive DAT; Negative Eluate; Specific to auto-anti P
