A solid-phase antiglobulin test.

Abstract

A solid-phase test (SPT), a machine-readable adaptation of the indirect anti-human globulin test (IAHG), is described. The SPT level of sensitivity was comparable to that of the manual IAHG test for the detection of IgG antibodies and was compared with manual pretransfusion compatibility tests. The average difference from the mean of duplicate SPT results was 5.94 percent of the optical density value. The data also demonstrated a linear and overlapping relationship between the scores of manual IAHG tests and SPT optical density values. The accuracy of the SPT declined slightly as the concentration of red cell samples increased; the optimum concentration of immunoglobulin used in the preparation of the solid phase was about 275 mg per l. The 97.5th percentile of negative tests occurred at the same optical density (0.13) when serums from either healthy donors or hospitalized patients were tested. Compatibility tests completed on 1304 blood samples from donors and 437 serum samples from hospitalized patients showed that 1.38 percent of results were SPT-positive and manual IAHG-negative, and 5.37 percent were SPT-negative and manual IAHG-positive. The lowest possible score in the manual test was allocated to 97.14 percent of the latter group, indicating good correlation between the two techniques.