Hemolysin test as a tool to screen high-titer Group O platelet apheresis donors: A prospective study

Minor ABO-incompatible apheresis platelet transfusion poses a risk of hemolytic transfusion reactions in non-Group O recipients when donor's plasma possesses unusual high titers for anti-A and anti-B. The aim was to determine whether the hemolysin test can be used as a screening tool to predict high-titer Group O platelet apheresis donors.

A prospective study, with Group O platelet donor's samples, was tested for hemolysin test and antibody titration test in parallel. Antibody titration was also performed on products suspended in platelet additive solution (PAS). Hemolysin test was assessed for diagnostic accuracy against antibody titration. Chi-square test and Mann-Whitney U-test were used to determine the relationship between the hemolysin test and antibody titration.

Among 107 Group O platelet donations, median anti-A and anti-B titers in donors were 32 (8-128) and 32 (4-256), respectively. High titer (≥128) for ABO antibodies was seen in 18% of donations, whereas hemolysin test was positive in 69% of donations. Hemolysin test results differ significantly with antibody titration results (P = 0.03). Hemolysin test had higher sensitivity (89%) with a strong negative predictive value (94%). None of the products suspended in PAS had high-titer antibodies.

Adopting hemolysin test as a screening tool may label a large number of units (69%) unsuitable for ABO-incompatible platelet transfusion. Alternatively identifying donors with high antibody titer or positive hemolysin test and selectively suspending their product in PAS may be a cost-effective approach and certainly prevent high-titer antibodies in the product.