IMMUNOHEMATOLOGY AND BLOOD BANKING Flashcards
extracts made from the seed of plants which have blood group specificity
lectins
It is used as anti sera for antigen typing red cells
lectins
blood specificity : Anti - A
lectin :
Dolichos biflorus
blood specificity : Anti - B
lectin :
Bandeiraea simplicifolia
blood specificity : Anti - H
lectin :
Ulex europaeus
blood specificity : Anti - M
lectin :
Iberis amara
blood specificity : Anti - N
lectin :
Vicia graminea
blood specificity : Anti - T
lectin :
Arachis hypogea (peanut lectin)
blood specificity : Anti - Tn (Tn syndrome)
lectin :
Salvia sclaera
Anti-Tn or Tn syndrome is formerly known as
Permanent mixed-field polyagglutinability
It is the correlation of ABO antigens on red cells and the reciprocal agglutinating antibodies in the serum of the same individual
Landsteiner’s Rule / Landsteiner’s Law
won the nobel prize
Karl Landsteiner
year of the discovery of ABO blood group system
1901
first anticoagulant used and discovered by who
Sodium phosphate ; Braxton Hicks
the year 4th blood group (AB) was discovered (decastello & sturli)
1902
Universal donor of plasma
Group AB
- it has no antibodies in plasma
Universal donor of packed RBCs
Group O
- no antigens
Universal recipient of packed RBCs
Group AB
principle of forward typing
detection of ANTIGENS on patient’s RBC with known commercial ANTISERA
specimen and reagent used in forward typing
specimen: patient’s rbc
reagent: anti-sera
forward typing is also known as
front
cell
direct
formation of ABO antigens
5th-6th week of gestation (newborn, in utero)
peak production of ABO antigens
2-4 years of age
color of anti-sera: Anti-A
Blue
color of anti-sera: Anti-B
yellow
antisera used for Rh antigen that gives (+) or (-) for blood type
Anti-D
principle of reverse typing
detection of ABO antibodies (isoagglutinins) in serum of patient with known commercial RBCs
specimen and reagent used in reverse typing
specimen: patient’s serum
reagent: known cells or known commercial RBCs
formation of ABO antibodies
3-6 months of age
- not for newborn; maternal antibody is seen if used for newborn
peak production of ABO antibodies
5-10 years of age (continuous)
2 important classification of ABO antibodies
- IgM- cold reacting; react best at room temp; do not bind to complements
- IgG (immune antibodies - develops upon exposure causing hemolysis) - can cross placenta
used to washed out antibodies present
saline
unexpected reactions are obtained in the forward and/or reverse grouping
ABO Discrepancies
if there is antibody missing or extra antibody reacting, it has problem with patient’s ____
Serum (reverse grouping)
if there is antigen missing or extra antigen reacting, it has problem with patient’s ____
RBCs (forward grouping)
if the patient’s problem is both Serum and RBCs, in forward, RCBs must be ____ and _____ if reverse
in forward, RBCs must be washed and saline replacement if reverse
unexpected reactions due to:
- extra POSITIVE reactions
- WEAKLY or MISSING reactions
All ABO discrepancies must be ____ prior to reporting a patient or donor ABO group
resolved
it is usually the discrepant reactions
Weak reactions
it is much more common than antigen problems
antibody problems
steps in forward typing
step 1: anti-sera
step 2: RBC
steps in reverse typing
step 1: serum/plasma
step 2: known cells
Common sources of technical errors causing ABO discrepancies
- Incorrect or inadequate identification of blood specimens, test tubes, or slides
- Cell suspension either too heavy or too light
- Clerical errors or incorrect recording of results
- A mix-up in samples
- Missed observation of hemolysis
- Failure to add reagents
- Failure to add samples
- Failure to follow manufacturer’s instructions
- Uncalibrated centrifuge
- Overcentifugation or undercentrifugation
- Contaminated reagents
- Warming during centrifugation
Group I Discrepancies
problem:
- unexpected reaction with ____
- weakly reacting or missing ____
resolution:
- incubate patient’s _____________ @ RT for 15-30 minutes
- if still no reaction, incubate _____ @ ____ for 15-30 minutes
problem:
- REVERSE GROUPING
- ANTIBODIES
resolution:
- PATIENT’S SERUM with REAGENT A1 & B CELLS
- SERUM-CELL MIXTURE @ 4degC
examples of group I discrepancies
- Newborn (ABO antibody production not detectable until 3-5 months of age)
- Elderly (production of ABO antibody is depressed
- Leukemia (CLL) or Lymphoma (ML) or Patients using immunosuppressive drugs demonstrating hypogammaglobulinemia
Group II Discrepancies
problem:
- unexpected reaction with ____
- weakly reacting or missing ____
resolution:
- incubate patient’s _____________ @ RT for 30 minutes
- if still no reaction, incubate _____ @ ____ for 15-30 minutes
problem:
- FORWARD GROUPING
- ANTIGENS
resolution:
- patient’s RBC with reagent ANTI-SERA
- TEST MIXTURE @ 4degC
examples of group II discrepancies
- subgroups of A & B
- Leukemia - weakened A or B antigens
- Hodgkin’s disease - mimic depression of antigens
- Acquired B phenomenon - weak reactions with anti-B antisera (blood type A)
Group III Discrepancies
problem:
- unexpected reaction with ____
- protein or plasma abnormalities —>
resolution:
- forward grouping: wash patient’s RBCs several times with ____
- reverse grouping: ____ technique [serum=saline]
problem:
- FORWARD & REVERSE GROUPING
- ROULEAUX formation or PSEUDOAGGLUTINATION (false agglutination)
resolution:
- SALINE; wash RBC 2-3x; wash cord cells 6-8x (due to wharton’s jelly)
- SALINE REPLACEMENT (serum is removed and replaced by an equal volume of saline)
example of group III discrepancies
- Elevated levels of globulin - MM, Waldenstrom’s macroglobulinemia, other plasma cell dyscrasias, and certain moderately advance cases of Hodgkin’s lymphomas
- Elevated levels of fibrinogen
- Plasma expanders (Dextran & Polyvinylpyrrolidone)
- Wharton’s Jelly (cord samples)
ABO antigens are made up of _____ & _______
glycolipids and glycoproteins
precursor of A & B antigens (sugar)
Oligosaccharides
group in ABO discrepancies wherein discrepancies between forward and reverse grouping are due to ______
group IV; MISCELLANEOUS PROBLEMS
Group IV Discrepancies
problem:
- potent cold autoantibodies —> yield +coomb’s/antiglobulin test
resolution:
- incubate patient’s _____________ @ 37degC for short period of time —> washed saline 3x @37degC —> retype
if not successful:
- forward: patient’s rbc + ______
- reverse: reagent rbcs and serum can be _______ for 10-15 minutes, mixed, tested, and read @ 37degC
- convert the test to _____ if necessary
resolution:
- patient’s RBC
if not successful:
- 0.01 M dithiothreitol (DTT)
- incubate/warmed @ 37degC
- AHG Phase
Group IV Discrepancies
problem:
- Weakly reactive Anti-A or Anti-B
resolution:
- may not react at 37degC
if reverse typing is still negative:
- ________ (patient’s cells with patient’s serum) - remove cold autoantibody from serum
- the ______ can then be used to repeat the serum typing @ RT
- Cold autoabsorption
- absorbed serum
Group IV Discrepancies
problem:
- _______ - this happens to those blood types that have subgroups
resolution:
- _______ - produce small amount of Anti-H
- A2B & A2 - produce _____
- serum grouping can be repeated using at least 3 examples of _________(known reagent cells) and _________ control (patient’s serum mixed with patient’s rbcs)
- test patient’s rbc with ________ (lectin specific for A1 antigen)
problem:
- Unexpected ABO isoagglutinins
resolution:
- A1B & A1
- Anti-A1
- A1, A2, B cells ; O cells
- Autologous
- Dolichos biflorus
once the unexpected alloantibodies are identified, this should be used in the reverse grouping
reagent A1 and B cells that is negative for corresponding antigen
these are ABO water soluble substances found in saliva and other body fluids
ABH SECRETOR
Principle of detection in ABH secretor
based on agglutination inhibition/neutralization
secretor that produce A, B, H in secretions
SeSe and Sese
it is a non secretors; no A, B, H soluble substances found in secretions
sese
Glycoprotein
Type 1 precursor chain
B 1-3 linkage of D-galactose and N-acetylglucosamine
soluble substances in blood type A
A & H soluble substances
soluble substances in blood type B
B & H soluble substances
soluble substances in blood type AB
A, B, & H soluble substances
soluble substances in blood type O
H soluble substances
in agglutination inhibition/neutralization test, no agglutination means
positive
it has a lot of H antigens
O cells
it detects anti-IgG or anti-complement
AHG Testing (Coomb’s test)
reagent of AHG testing
Polyspecific AHG and Monospecific AHG
contain antibody to human IgG & C3d to component of human complement
Polyspecific AHG
in Polyspecific AHG, this complement may also be present
Anti-C3b
this type of reagent in coomb’s test can facilitate agglutination when RBCs have been sensitized with IgG or C3d or Both
Polyspecific AHG
commercially prepared polyspecific AHG contains antibody activity against ______
IgA and IgM HEAVY CHAINS
polyspecific mixture contains antibody activity to _____
KAPPA & LAMBDA LIGHT CHAINS