ABO DISCREPANCIES Flashcards
What are the causes of ABO discrepancy?
- TECHNICAL ERRORS 2. Sample Problems
Technical errors include identification and documentation error, reagent or equipment error, and standard operation procedure error.
What are some examples of technical errors that can lead to ABO discrepancy?
- Identification and documentation error
- Reagent or equipment error
- Standard operation procedure error
These errors can affect the accuracy of ABO typing.
What are potential sample problems related to red cells in ABO discrepancy?
- Extra antigens
- Missing/weak antigen
- Mixed field reactions
These issues can complicate the interpretation of blood types.
What are potential sample problems related to serum/plasma in ABO discrepancy?
- Extra antibodies
- Missing or weak antibodies
These can also affect the results of blood typing.
unexpected reactions in the serum/reverse typing
group 1 discrepancy
Most frequent discrepancies in blood typing
Group I discrepancies
What can cause unexpected reactions in serum or reverse typing?
Weakly reacting or missing antibodies
These reactions can indicate issues with the patient’s antibody production.
What might indicate that a patient has depressed antibody production?
The patient cannot produce ABO antibodies
This can lead to discrepancies in blood typing results.
What are the conditions associated with Group I discrepancies?
Newborns, Elderly patients, Patients with leukemia, Hypogammaglobulinemia (immunosuppressants), Congenital agammaglobulinemia, Patients with bone marrow transplant, ABO antibodies may have been diluted by plasma transfusion, ABO subgroups.
What are the rare conditions associated with Group I discrepancies?
Chimerism (mixed), Blood transfusion, Transplanted bone marrows, Exchange transfusions, Fetal maternal bleeding.
unexpected reactions in group I discrepancies?
Unexpected reactions such as extra antibodies and depressed/negative antibody production.
What is the first step in resolving unexpected reaction in Group I discrepancies?
Obtain patient history and diagnosis.
What is the incubation process for the patient’s serum?
Incubate the patient’s serum with reagent A1 and B cells at room temperature for approximately 15-30 minutes.
What should be done if there is still no reaction after initial incubation?
Incubate the serum-cell mixture at 4 degrees Celsius for 15-30 minutes and add more serum to the reaction.
• Due to unexpected reactions in the
FORWARD TYPING
• Least frequently encountered
•Due to weak (extra) or missing antigens
Group Il discrepancies
What are the conditions for Group II discrepancies?
Subgroups of A (or B) may be present. Leukemias may yield weakened A or B antigens. Hodgkin’s disease has been reported in some cases to mimic the depression of antigens.
What is the Acquired B phenomenon?
It refers to diseases of the digestive tract affecting B antigens.
Test patient RBCs with ES4 (monoclonal Anti-B clone) and test with acetic anhydride.
What is the first step in resolving Group II discrepancies?
Incubate the patient’s red cells and the antisera at room temperature for up to 30 minutes.
What should be done if there is still no reaction after the initial incubation in group 2 discrepancy?
Incubate the serum-cell mixture at 4 degrees Celsius for 15-30 minutes with O and auto control cells.
Can RBCs be pretreated before testing?
Yes, RBCs can be pretreated with enzymes and retested with reagent antisera.
•Due to FORWARD and REVERSE
TYPING problems
•Plasma or protein abnormalities
•Rouleaux formation
Group III discrepancies
Group Ill discrepancies
CONDITIONS:
•Multiple myeloma, Waldenstrom’s macroglobulinemia, Hodgkin’s
lymphoma
•Elevated fibrinogen
•Plasma expanders (dextran, polyvinylpyrolidone)
•Wharton’s jelly in cord blood samples
Group Ill discrepancies
RESOLUTION:
•washing RBCs with saline prior to typing
•saline replacement procedure
What are Group IV discrepancies?
Both forward and reverse typing problems, as well as miscellaneous problems.
What conditions can lead to Group IV discrepancies?
Cold reactive autoantibodies, circulating RBCs of more than one ABO blood group, unexpected ABO isoagglutinins, and unexpected non-ABO alloantibodies.
Group IV discrepancies
RESOLUTION FOR RED BLOOD CELLS:
• Incubate patient RBCs at 37 degree Celsius (short period)
• Wash RBCs with saline (3x) and retype
•IF UNSUCCESSFUL:Pretreatment of RBCs with 0.01 M DTT
Group IV discrepancies
RESOLUTION FOR SERUM:
• mix RBCs and serum then warm at 37°C, and retype
• identify the alloantibody
