Development of an economic and efficient strategy to detect HBsAg: Application of “gray-zones” in ELISA and combined use of several detection assays

Abstract

BackgroundELISA and CMIA are commonly used for detection of HBsAg. However, few investigations have been performed to evaluate their value in clinical practice, especially when jointly used. A reasonable and economic HBsAg testing algorithm is in great need. MethodsA total of 161,426 specimens in China were tested for 5 serum HBV markers with commonly used ELISA kits. 498 of these specimens were further tested for HBsAg by another ELISA kit, a CMIA kit and an HBsAg confirmatory assay. ResultsThe sensitivities of the 2 ELISA kits were 76.21% and 88.42%, respectively. However, when using “gray-zones”, the sensitivities were significantly improved to 97.43% and 96.43%. Furthermore, the combined use of the 2 ELISA kits and their “gray-zones” improved the sensitivity to 99.04%. Nevertheless, 2.91% of the samples with S/CO values below the lower “gray-zone” limits were reactive by the CMIA kit and then confirmed as HBsAg positive. However, 71.43% of the samples with HBsAg values within 0.05 and 0.10IU/ml detected by the CMIA kit could not be confirmed. ConclusionsAs a rational and economic strategy, combined use of “gray-zones” in ELISA and several different detection assays can significantly increase the efficiency of HBsAg detection.