3. ABID Look at the panel and check Phases that have positive reactions Phase that do not have positive reactions Are there different reaction strengths recorded? Are there reactions at different phases? Patient auto control Is it negative or positive? These are all clues to help with identification
4. Look for Clues 1 Reactions are all at AGH Reaction strength is different at cell 3 Different reaction strengths can indicate: dosage and/or multiple antibodies Patient auto control is negative, indicating a possible alloantibody
5. Begin Ruling Out Use only panel cells that have no reaction recorded in any phase. Begin with cell #2 Follow with cells #5 and #6 What is left?
6. Ruling Out When ruling out Use only cells where no reaction is recorded Go one cell at a time and mark out antigens that are positive Watch out for antigens that show dosage Kidd, Kell, Duffy, MNS, Lewis If both are present on the cell then can not be ruled out Look for a pattern to show up especially if only one antibody is present in patient serum
7. Lets begin! The first cell with a negative reaction is panel cell 2. Go across cell 2 and mark out all antigens that are positive.
8. Panel Red Cell #2 All positive antigens for panel cell #2 have been marked out except for M and N. M and N travel together and therefore show dosage. In order to mark out antigens showing dosage, one antigen must be positive and the other negative.
9. Continue Ruling out Antigens Continue ruling out Use only panels cells where no reaction occurred After all antigens are marked out look and see what is left.
10. What is left? After ruling out: Check what antigens are not marked out In our example Antigen s and K are not marked out What are we testing for? Patient serum/plasma for unexpected antibodies Antibodies react with: antigens on red cells Consider the Rule of Three when interpreting results
11. Rule Of Three There must be three antigens that react positively with the patients serum/plasma. There must be Three antigens that react negatively with the patients serum/plasma. If not, use selected cells with or without the antigen in question to meet the Rule of Three
12. What About our Example? Antigen K – Meets the rule of three Does not match the reaction pattern Cannot rule out yet Antigen s – Meets the rule of three Does match the reaction pattern Cannot rule out yet
13. How to Resolve Phenotype the patient red cells for antigen K and s If patient is negative for the antigen then the antibody could be present If patient is positive for the antigen then the reactions would not be from the corresponding antibody
14. Patient Phenotype The patient is positive for the K antigen; therefore will not make Anti-K. (Remember Landsteiner’s Rule!) The patient is negative for the s antigen; therefore the antibody is most likely Anti-s
15. Interpretation of Results Based on the panel reactions and the antigen test results: Our patient has a possible anti-s in his serum/plasma. When you get a chance, ask if you might review some panels at your clinical site.
