ABO BLOOD GROUP SYSTEM Flashcards
No soluble antigen bodily fluid
CSF
Rule stating that normal, healthy individuals possess ABO antibodies to the ABO blood group antigens absent from their red cells
Landsteiner Law/Rule
He demonstrated that an individual inherits one ABO gene from each parent and that these two genes determine which ABO antigens are present on the RBC membrane
Bernstein in 1924
Which chromosome is being ovcupied by ABO Gene
Chromosome 9
detection of antigen in the RBC using known antisera
Forward/Direct/RedCell Grouping
detection of antibodies in the patient’s serum using known red cells
Backward/ Indirect/ Reverse/Serum Grouping
Antisera Colors for Forward Blood Typing
A- Bromthymol Blue
B- Acriflavin Yellow
Presence of Anti-H Ag
Bombay Phenotype
process of dissociating antibody from red cell surface
ELUTION
process of removing antibodies in the serum using known red cells
ADSORPTION
Universal donor in Red cell transfusion
Blood type O
Universal recipient in Red Cell Transfusion
Blood type AB
Universal donor in Plasma transfusion
Blood type AB
Universal recipient in Plasma transfusion
Blood type O
A and B antigens are produced on ___ day of fetal life/ __ to
___ weeks of fetal life
37th day
5 to 6 weeks
It is the presence or absence of the ABH antigens on the red cell membrane
H gene
Presence or absence of ABH antigens in secretions
SE genes
What are the basic precursors of ABH antigen
Type 1 beta precursor chain (beta 1-3 linkage)
Type 2 precursor chain (beta 1-4 linkage)
It is a type of precursor which has a linkage between the terminal D- galactose and N- acetylglucosamine, function as to produce soluble antigens that depends if it is a secretor or non-secretor
Type 1: Beta 1-3 linkage
It is a type of precursor in which it has a linkage between the terminal D-galactose and N-acetylglucosamine, mainly for production of Ag in red cell membrane
Type 2: Beta 1-4 linkage
Reactivity of anti-H antisera or anti-H lectin with ABO Blood Group
H Antigenicity
Seed extracts that can agglutinate red cells with some degree of specificity.
LECTINS
It is the type of phenotype characterized by Absence of H, A & B antigens
Bombay phenotype
Reaction with Ulex europaeus
NEGATIVE
Three Categories of BOMBAY Phenotype
H-deficient, Non secretor: Classic bombay
H-Partially Deficient ; Non Secretor: Weak forms of A and B antigens
H deficient Secretor: Para bombay
Types of H antigen
H1 and H2- Simple straight chain glycolipids
H3 and H4- Complex/Branched chains
B Phenotypes
B3- mixed field pattern of agglutination w/ anti-B and anti-AB
Bx- weak agglutination with anti-B and anti-AB antisera
Bm-unagglutinated by anti-B and anti-AB
Belm- unagglutinated by anti-B or anti-AB
How to resolve ABO discrepancies
Repeat test on the same sample by using saline suspension of RBCs if the test was initially performed using RBCs suspended in serum or plasma
What are the Clerical errors in IMHM laboratory processing
– Mislabeled tubes
– Patient misidentification
– Inaccurate interpretations recorded
– Transcription error
– Computer entry error
What are the problems in Reagent and Equipment in IMHM laboratory
– Using expired reagents
– Using an uncalibrated centrifuge
– Contaminated or hemolyzed reagents
– Incorrect storage temperatures
What are the Procedural errors in IMHM laboratory
– Reagents not added
– Manufacturer’s directions not followed
– RBC suspensions incorrect concentration
– Cell buttons not resuspended before grading agglutination
It is a group of discrepancy that caused unexpected reactions in reverse typing due to Weakly reacting or missing antibodies, and is the most common cause of ABO discrepancy
Group 1 Discrepancies
Populations which can exhibit Group 1 discrepancy
- Newborns
- Elderlies
- Leukemic patients
- Patients taking immunosuppressive drugs
- Patient’s with congenital agammaglobulinemia 6. Patients with BM Transplantation
- Patients whose ABO antibodies are diluted with plasma transfusion or exchange
- ABO subgroups
- Chimerism- presence of two cell populations in a single individual
Resolution for Group 1 discrepancies
Incubation of serum with reagent A1 and B cells at room temperature for 15 to 30 minutes
If no reaction after centrifugation, incubate at 4C for 15 to 30 minutes
It is a type of group discrepancy in which unexpected reactions in the Forward grouping due to weakly reacting or missing antigens, less frequently encountered
Group 2 discrepancies
It is a type of phenomenon that modifies immunodominant sugar of blood group A to Group B, negative reaction in autologous serum test
Acquired B phenomenon
Acquired B antigen will not agglutinate in what pH
pH higher than 8.5
pH lower than 6.0
What treatment is used for Acquired B Phenomenon
Acetic Anhydride
What is the resolution for group 2 discrepancies
Incubate test mixture at room temperature for up to 30 minutes
If negative incubate at 4C for 15-30 minutes
Autocontrol and O must always be tested with patients sample
This group causes problems in forward and reverse grouping due to PLASMA PROTEIN ABNORMALITIES which can result to rouleaux formation and pseudo-agglutination
Group 3 discrepancies
What is the resolution for Group 3 discrepancies
Perform saline dilution or saline replacement technique
Washing cord cells six-eight times with saline to remove Wharton’s jelly
Causes for group 4 discrepancies
Presence of cold-reactive autoantibodies (ANTI-I)
Patient has circulating RBC with more than one blood type (AB PATIENT)
Unexpected ABO isoagglutinins
Unexpected non-ABO isoagglutinins
Cis-AB- refers to inheritance of both AB genes from one parent carried on one chromosome and an O gene inherited from another parent
Resolution for Group 4 discrepancies
Potent cold autoantibodies can cause spontaneous agglutination of the patient’s cells
RBCs could be incubated at 37oC for a short period, then washed with NSS and retyped
If not successful in resolving forward type, treat patient’s RBC with 0.01M dithiothreitol to disperse IgM related agglutination
As for the serum, the reagent RBCs and serum can be warmed to 37oC, then mixed, retested and read at 37oC
If the reverse typing is negative - Autoabsorption is done to remove autoantibody
Unexpected ABO is o agglutinins in the patient’s serum react at RT – A2 and A2B individuals who can produce naturally occurring anti-A1 and A1B who produce naturally occurring anti-H
Specificity of the antibody can be determined by examining the pattern of reactivity
Unexpected all o antibodies in the patient’s other than ABO is o agglutinins
Panel could be performed with the patient’s serum
