Role of gel based technique for Coomb's test.

The direct (DAT) and indirect antiglobulin tests (IAT) are one of the most important diagnostic tools used in the investigation of immune mediated disorders. Recently, transfusion laboratories have seen the introduction of column technology in the form of the gel technology (GT). Aim of this study is to compare the conventional tube tests (CTT) and the GT for Coomb's test and to evaluate their sensitivity and specificity. 1656 samples were included in this study, in which 1054 samples were subjected to IAT and 602 samples were subjected to DAT Of the 602 samples tested for DAT, 587 (97.5%) showed concordant DAT results. DAT by the GT could detect 8.6% positivity as compared to 6.1% by CTT. The sensitivity and specificity of the GT was 100% and 97.3% respectively and its negative predictive value was 100%. Among the 1054 samples for IAT, 1041 (98. 8%) showed concordant results. The IAT by the GT showed 6.6% positivity as compared to 5.4% positivity by CTT The sensitivity, specificity and the positive and negative predictive value were 100%, 97.7%, 81.4% and 100% respectively. In conclusion, the GT is a better alternative to the CTT for both DAT and IAT. The GT is highly recommended to be implemented as a routine method of testing in all zonal / regional blood transfusion centers.