What is ABO discrepancy?

An ABO discrepancy exists when the result of an ABO RBC typing, or forward type, does not agree with the result of the plasma typing, or reverse type. It is extremely important in the clinical laboratory to record these initial discrepant results.

What causes ABO discrepancies?

Blood group discrepancy develops when the results of red cell typing do not match with plasma typing, or if the previous and present results do not match3. ABO discrepancies may be due to clerical errors or technical problems with a sample or during testing.

What are the four ABO discrepancies?

The table that follows provides four useful categories. Weak, missing reactions (including mixed field) in the forward (red cell) typing. Unexpected reactions in the forward (red cell) typing. Weak or missing reactions in the reverse (serum) typing.

What are the different ABO discrepancies?

Group I – Discrepancies that are associated with unexpected reactions in the reverse grouping. Group II – Discrepancies that are associated with unexpected reactions in the forward grouping. Group III – Discrepancies between forward and reverse grouping caused by protein or plasma abnormalities.

What is the principle of ABO blood grouping?

Principle: The ABO and Rh blood grouping system is based on agglutination reaction. When red blood cells carrying one or both the antigens are exposed to the corresponding antibodies they interact with each other to form visible agglutination or clumping.

What is detected in ABO reverse grouping?

The back/reverse type mixes an individual’s plasma with reagent RBCs positive for antigen A, and separate reagent RBCs positive for B antigen. The test also measures visual agglutination or lack of agglutination. Most ABO antibodies are immunoglobulin (Ig) M.

What is forward and reverse typing?

Forward typing- A blood typing procedure whereby patient red blood cells are mixed with Anti-A and Anti-B reagents. Reverse typing – A blood typing procedure where patient serum is mixed with reagent A cells and reagent B cells. The results should be the opposite of forward typing.

What kind of discrepancies are there in ABO blood group detection?

1.1 To resolve ABO and Rh blood group discrepancies. 1.2 Blood group discrepancies exist when the reaction in the forward group (red cells) does not match the reactions in the reverse grouping (plasma/serum), when expected reactions are weak or negative, or if the previous and current results do not match.

Who is the father of blood group?

Karl Landsteiner. Father of blood grouping and immunochemistry.

What are limitations of ABO grouping?

The main limitation of using blood groups to identify people is that they are much more effective at eliminating people and much less effective at positively identifying people. For example, about 37% of Americans are type O+.

What is reverse ABO typing?

Reverse Typing. Reverse typing refers to the testing of a patient’s serum for the presence of ABO antibodies. The patient’s serum is mixed with known red cells in a test tube. A specified number of drops of patient serum are placed into each of three properly labeled tubes.

What blood group may be transfused when there is not time to resolve an ABO discrepancy?

6.3. 2.6 If the discrepancy is still not resolved, consult with a senior technologist for further direction. Select Group O red cells and Group AB plasma for transfusion.

When do you have an ABO discrepancy?

ABO discrepancy is a generic term for a variety of situations in which the interpretation of a patient or donor ABO grouping results is unclear. These discrepancies occur when unexpected negative or positive reactions occur in the forward or reverse grouping.

What causes ABO group discrepancies in three case studies?

The most common causes for these discrepancies are: 1) Unexpected ABO isoagglutinins, as represented in Case History #3. This type of discrepancy is seen in Group A2, A2B and some other subgroups of A. To resolve the discrepancy, several examples of Group A1, A2, B, and O red cells and an auto-control should be tested.

What causes an ABO blood group discrepancy?

ABO blood Group System: ABODiscrepancies: • ABO discrepancies happen when there is no match in results between forward and reverse grouping(Cell type and Back type). • Since production of ABO antigens is genetically controlled, they are less vulnerable toproblems than does the production ofABO antibodies.

What causes a discrepancy in ABO isoagglutinins?

The most common causes for these discrepancies are: 1) Unexpected ABO isoagglutinins, as represented in Case History #3. This type of discrepancy is seen in Group A2, A2B and some other subgroups of A. To resolve the discrepancy, several examples of Group A1, A2, B, and O red cells and an auto-control should be tested.

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