Comparison of the two fully automated anti-HCMV IgG assays: Abbott Architect CMV IgG assay and Biotest anti-HCMV recombinant IgG ELISA

Objective and background: To assess the performance characteristics of two fully automated human cytomegalovirus (HCMV) antibody tests.

Materials and methods: Samples from negatively or not pre-screened blood donors were tested by the Biotest anti-HCMV recombinant IgG enzyme-linked immunosorbent assay (ELISA) in comparison to the Abbott Architect CMV IgG assay [chemiluminescent microparticle immunoassay (CMIA)]. For clarification, samples with discordant results between both assays were subjected to supplemental testing for anti-HCMV IgG, IgM and HCMV DNA in plasma.

Results: From 4938 samples tested, 362 delivered positive results in both assays (7.3%). 91 (1.8%) samples were discordant. Of 43 (two not further tested) samples positive only by ELISA, 41 were false positive, one true positive and one indeterminate. Of 45 (one not further tested) samples positive only by CMIA, 20 were false positive, 9 indeterminate and 16 true positive. Anti-HCMV IgM and HCMV DNA testing from the plasma were negative in indeterminate samples. Considering the results of supplemental testing, the CMIA achieved altogether better results concerning resolved sensitivity, resolved specificity as well as negative predictive value. Both assays had an inferior positive predictive value, with a better result for CMIA.

Conclusion: Overall, the performance characteristics of the CMIA were better than those of the ELISA. Owing to the inferior positive predictive value, positive test results require confirmation if blood products from donors with remote HCMV infection should be administered.