Multicenter evaluation of four immunoassays for the performance of early diagnosis of COVID-19 and assessment of antibody responses of patients with pneumonia in Taiwan

Lin, Yi-Chun; Lee, Yu-Lin; Cheng, Chien-Yu; Tseng, Wen-Pin; Wu, Jhong-Lin; Lin, Chien-Hao; Chung, Ming-Yi; Kang, Chun-Min; Lee, Ya-Fan; Chen, Cheng-Pin; Huang, Chien-Hua; Liu, Chun-Eng; Cheng, Shu-Hsing; Chen, Shyr-Chyr; Chen, Shey-Ying; Hsuehd, Po-Ren

Background/purpose: Our study goals were to evaluate the diagnostic performance of four anti-SARS-CoV-2 antibodies tests and the differences in dynamic immune responses between COVID-19 patients with and without pneumonia. Methods: We collected 184 serum samples from 70 consecutively qRT-PCR-confirmed COVID-19 patients at four participating hospitals from 23 January 2020 to 30 September 2020. COVID-19 pneumonia was defined as the presence of new pulmonary infiltration. Serum samples were grouped by the duration after symptom onset on a weekly basis for antibody testing and analysis. The four immunoassays: Beckman SARS-CoV-2 IgG/IgM (Beckman Test), Siemens (ADVIA Centaur®) SARS-CoV-2 Total (COV2T) (Siemens Test), SBC COVID-19 IgG ELISA (SBC Test) and EliA SARS-CoV-2-Sp1 IgG/IgM/IgA P2 Research (EliA Test) were used for detecting the SARS-CoV-2 specific antibodies. Results: The sensitivity of all tests reached 100% after 42 days of symptom onset. Siemens Test, the only test detecting total anti-SARS-CoV-2 antibodies, had the best performance in the early diagnosis of COVID-19 infection (day 0-7: 77%; day 8-14: 95%) compared to the other 3 serological tests. All tests showed 100% specificity except SBC Test (98%). COVID-19 patients with pneumonia had significantly higher testing signal values than patients without pneumonia (all p values < 0.05, except EliA IgM Test). However, Siemens Test and SBC Test had highest probability in early prediction of the presence of COVID-19 pneumonia. Conclusion: Chronological analysis of immune response among COVID-19 patients with different serological tests provides important information in the early diagnosis of SARS-CoV-2 infection and prediction of the risk of pneumonia after infection.