Evaluation of a solid-phase test for erythrocyte antibody screening of pregnant women, patients and blood donors.

UNLABELLED

We have studied a previously described solid-phase test (SPH) for screening and identification of antibodies directed against erythrocyte antigens, in large sample numbers and throughout routine processing. The screening results of all samples from pregnant women, patients and blood donors (n = 36,701) sent to our blood bank from August 1992 to July 1993 were compiled and evaluated. Pregnant women were screened by the SPH-antiglobulin technique (IAT) and the SPH-enzyme-enhanced technique (ENZ), while the patients and blood donors were screened only by the SPH-IAT. Samples with known alloimmunization were excluded from this study. Positive screening reactions were further investigated by the SPH-IAT and SPH-ENZ techniques, the manual hemagglutination tests low ionic-strength solution IAT and 2-stage papain. Pregnant women: A positive reaction in one or both of the SPH tests was found in 1.2% of the samples. The SPH tests identified 99 (98.0%) and the manual methods 79 (78.2%) of a total of 101 antibodies. Of the identified antibodies, 61 were to antigens in the Rh blood group system, including 34 Rh immune globulin. The remainder had specificity directed against antigens K, Jka, M, S, Le(a) and Le(b).

PATIENTS

A positive reaction in the SPH-IAT test occurred in 0.9% of the samples. The antibodies identified had specificity directed against antigens D, C, c and E in the Rh blood group system. The remainder had specificity directed against antigens Fya, K, Jka, M and Le(a). All antibodies identified by SPH-IAT, except 1 anti-M and 2 anti-Le(a), were also identified by manual methods. Blood donors: A positive reaction in the SPH-IAT test was noted in 0.7% of the samples. The identified antibodies had specificity directed against antigens D, C, E, Fya, K and M. All antibodies identified by the SPH-IAT, except 1 anti-D found in a sample from an RhD(+) male, were also identified by the manual methods. This study indicates that the SPH-IAT test is sensitive for detecting anti-M. This was also indicated for the SPH-ENZ test concerning the Jka antibody. An advantage of using solid-phase antibody screening tests for a larger series of samples is the possibility of automated sample identification, dilution, dispensing and interpretation of results. The SPH-IAT and the SPH-ENZ tests permitted us to select test cells, preferably from our own donor pool. We conclude that the SPH-IAT and SPH-ENZ tests are suitable for routine antibody screening of pregnant women and the SPH-IAT test for screening patients and blood donors.