In ABO/Rh typing with strong positives and zero reactivity of A1 and B cells, what should be done next?

In ABO/Rh typing with strong positives and zero reactivity of A1 and B cells, what should be done next?

• A. Repeat ABO red cell type and include a control
• B. Perform Du testing
• C. No further testing required
• D. Incubate ABO typing at room temperature

Answer: (A)

When ABO typing results don’t align, the priority is to verify the test itself. If there are strong agglutinations in forward typing but the reverse typing with A1 and B cells shows no reactivity, this pattern likely reflects a technical issue or sample problem rather than a true ABO phenotype. The best next step is to repeat the red cell (forward) typing and include proper controls to confirm the procedure is working correctly. Use a fresh patient sample, ensure the cell suspension is prepared properly, and check for factors like rouleaux or reagent performance. Include a positive control (a known ABO type) and a negative control to confirm that any agglutination is due to specific antigen–antibody interactions. If the repeat confirms the discrepancy or remains incongruent, additional testing can be pursued, but repeating with controls is the essential next move.

When ABO typing results don’t align, the priority is to verify the test itself. If there are strong agglutinations in forward typing but the reverse typing with A1 and B cells shows no reactivity, this pattern likely reflects a technical issue or sample problem rather than a true ABO phenotype. The best next step is to repeat the red cell (forward) typing and include proper controls to confirm the procedure is working correctly. Use a fresh patient sample, ensure the cell suspension is prepared properly, and check for factors like rouleaux or reagent performance. Include a positive control (a known ABO type) and a negative control to confirm that any agglutination is due to specific antigen–antibody interactions. If the repeat confirms the discrepancy or remains incongruent, additional testing can be pursued, but repeating with controls is the essential next move.