Group O pattern in forward and reverse typing would be best described by which option?

Group O pattern in forward and reverse typing would be best described by which option?

• A. Forward: Anti-A positive; Anti-B positive; A cells positive; B cells positive
• B. Forward: Anti-A negative; Anti-B negative; A cells negative; B cells negative
• C. Forward: Anti-A positive; Anti-B negative; A cells positive; B cells negative
• D. Forward: Anti-A negative; Anti-B positive; A cells negative; B cells positive

Answer: (B)

Group O red cells lack both A and B antigens, yet the serum contains antibodies against them (anti-A and anti-B). In forward typing, you test the patient’s red cells with anti-A and anti-B. Because there are no A or B antigens on the patient’s cells, there is no agglutination with either antisera, so both anti-A and anti-B reactions are negative, and the patient cells themselves would show no reactivity with A or B cell controls. That pattern corresponds to this option. In reverse typing, you would expect the patient’s serum to agglutinate both A and B cells because it contains anti-A and anti-B antibodies. So the full Type O profile is negative results in forward typing but positive results in reverse typing. The other patterns describe A, B, or AB phenotypes, which is why they don’t fit Type O.

Group O red cells lack both A and B antigens, yet the serum contains antibodies against them (anti-A and anti-B). In forward typing, you test the patient’s red cells with anti-A and anti-B. Because there are no A or B antigens on the patient’s cells, there is no agglutination with either antisera, so both anti-A and anti-B reactions are negative, and the patient cells themselves would show no reactivity with A or B cell controls. That pattern corresponds to this option.

In reverse typing, you would expect the patient’s serum to agglutinate both A and B cells because it contains anti-A and anti-B antibodies. So the full Type O profile is negative results in forward typing but positive results in reverse typing. The other patterns describe A, B, or AB phenotypes, which is why they don’t fit Type O.