Serologic and Molecular Biologic Methods for SARS-associated Coronavirus Infection, Taiwan

Wu, Ho-Sheng; Chiu, Shu-Chun; Tseng, Tsan-Chang; Lin, Szu-Fong; Lin, Jih-Hui; Hsu, Yu-Fen; Wang, Mei-Ching; Lin, Tsuey-Li; Yang, Wen-Zieh; Ferng, Tian-Lin; Huang, Kai-Hung; Hsu, Li-Ching; Lee, Li-Li; Yang, Jyh-Yuan; Chen, Hour-Young; Su, Shun-Pi; Yang, Shih-Yan; Lin, Ting-Hsiang; Su, Ih-Jen

Severe acute respiratory syndrome (SARS) has raised a global alert since March 2003. After its causative agent, SARS-associated coronavirus (SARS-CoV), was confirmed, laboratory methods, including virus isolation, reverse transcriptase–polymerase chain reaction (RT-PCR), and serologic methods, have been quickly developed. In this study, we evaluated four serologic tests ( neutralization test, enzyme-linked immunosorbent assay [ELISA], immunofluorescent assay [IFA], and immunochromatographic test [ICT]) for detecting antibodies to SARS-CoV in sera of 537 probable SARS case-patients with correlation to the RT-PCR . With the neutralization test as a reference method, the sensitivity, specificity, positive predictive value, and negative predictive value were 98.2%, 98.7%, 98.7%, and 98.4% for ELISA; 99.1%, 87.8%, 88.1% and 99.1% for IFA; 33.6%, 98.2%, 95.7%, and 56.1% for ICT, respectively. We also compared the recombinant-based western blot with the whole virus–based IFA and ELISA; the data showed a high correlation between these methods, with an overall agreement of >90%. Our results provide a systematic analysis of serologic and molecular methods for evaluating SARS-CoV infection.