Results of red cell antibody screening assays from 2,500 laboratories in 10 external quality assessment programs:...

Red cell antibodies can cause severe or fatal hemolytic transfusion reactions and hemolytic disease of the fetus and newborn. Screening for antibodies, such as anti-D, has been applied over decades for any transfusions and pregnancies. A comparison of sensitivities across laboratories is lacking for such antibody assays.

We investigated the detection rates for defined antibody concentrations of anti-D, the most common trigger of adverse outcomes. In a concerted effort among 10 providers of external quality assessment and proficiency testing programs, 4 spiked samples were tested by exactly 2,500 laboratories applying their clinical routine procedures, covering 4 test principles, more than 24 test cells, and diagnostic devices from 5 manufacturers.

The sensitivity of the assay depended on the test principle. Detection rates correlated with anti-D antibody concentrations: 0.1 IU/mL and 0.025 IU/mL can reliably be recognized. Some assays enabled detection at 0.01 IU/mL, and only a few at 0.005 IU/mL. Erythrocyte-magnetized technology and solid phase red cell adhesion performed better than various modifications of the column agglutination technology. The conventional test tube technology, depending on visual reading, was least sensitive.

The results show options for action to improve antibody detection, may support a practice change to optimize routine strategies of red cell antibody screening, and can guide studies to evaluate the clinical impact.