Detection of and antigens in serum using a single quantitative enzyme immunoassay.

and antigen detection assays are commonly used diagnostic tools. However, a high level of cross-reactivity between these antigens prevents definitive pathogen identification by these assays alone. Retrospective analysis of 3,529 patients with and antigen testing performed on the same serum sample yielded an overall percent agreement of 99.3% (3,506 of 3,529; kappa: 0.859) between the two assays, suggesting that use of a single assay to detect both antigens may be an alternative diagnostic approach. We assessed performance of the Gotham BioTech antigen (GBA) enzyme immunoassay (EIA) (Portland, Maine) for detection of and antigens in serum. Comparison to the MiraVista Diagnostics (MVB) EIA showed 100% positive (24 of 24), negative (57 of 57), and overall (81 of 81) percent agreement. Additionally, 171 sera were used to compare the GBA EIA to the MiraVista Diagnostics (MVH) EIA, which showed 91.3% (63 of 69), 98% (100 of 102), and 95.3% (163 of 171) positive, negative, and overall percent agreement, respectively. Among eight patients with discordant GBA/MVH EIA results, seven had additional fungal testing performed, and results suggested that the MVH and GBA results were inaccurate for two and five samples, respectively. Overall, this study suggests that the GBA EIA has a high level of agreement with both of the commonly used, individual and antigen EIAs. By taking advantage of the high level of cross-reactivity between and antigen EIAs, utilization of a single antigen detection assay for these fungi provides an opportunity to optimize test utilization and decrease patient cost while maintaining a high level of diagnostic accuracy.