Superiority of gel centrifugation in antibody screening and identification.

We report on the direct comparison of gel centrifugation technique and tube testing for antibody screening (ABS) under controlled routine conditions. 3,000 blood samples were screened for antibodies (AB) by gel centrifugation (ID-System, bromelin 37 degrees C and room temperature, indirect antiglobulin test with LISS) and a sensitive tube test (TT; bromelin two-phase test, 37 degrees C and room temperature, and indirect antiglobulin test with 22% bovine albumin) in parallel. By ID significantly more relevant and potentially hemolytic AB (51 vs. 35 AB/1.7 vs. 1.2%) could be detected: anti-E 4, -C 1, -D 4, -CW 2, -c 2, -Jk(a) 2, -Jk(b) 1. Eleven of these even remained negative in TT when retested with increased sensitivity and taking additional (homozygous) test cells. In addition, naturally occurring but rarely hemolytic AB (35 vs. 23 AB/1.2 vs. 0.8%) were more frequently detectable by ID: anti-Le(a) 6, -Le(b) 2, -P1 6. In contrast, only two AB were only positive in TT: anti-Le(a) 1, -Le(a, b) 1. The main disadvantage of the ID was its frequent positivity (7.7 vs. 4.3%) due to irrelevant cold AB (anti-I, -HI, -H) and unspecific factors. This can be partly reduced by omission of the bromelin test at room temperature (ID 3.0%, TT 1.5%) as the detection of relevant AB is not affected. The frequency of naturally occurring AB was still the same as in TT (0.7%) when bromelin at room temperature was omitted in both techniques. Further advantages of the ID are simplicity, small volumes of sera and reagents, and easy evaluation.