Diagnostic performance of immunochromatography assay for rapid detection of IgM and IgG in coronavirus disease 2019

Abstract

Serologic assays have been developed to detect infection with coronavirus disease 2019 (COVID-19). This study was conducted to evaluate the diagnostic performance of an immunochromatography-based assay of human serum for COVID-19. The present study enrolled 149 subjects who had been tested by real-time reverse transcription-polymerase chain reaction (RT-PCR) for COVID-19 and were classified into two groups: 70 who were positive for COVID-19 and 79 who were negative for COVID-19 based on RT-PCR. An immunochromatography-based COVID-19 immunoglobulin G (IgG)/immunoglobulin M (IgM) rapid test on the sera of the study population was applied to measure the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and receiver operating characteristic (ROC) curve compared to RT-PCR, with a 95% confidence interval (CI). IgM or IgG antibodies were detected in 65 subjects (92.9%) classified as positive for COVID-19 and in three subjects (3.8%) classified as negative for COVID-19. The sensitivity and specificity percentages for IgM or IgG antibodies were 92.9% (95% CI: 84.1-97.6) and 96.2% (95% CI: 89.3-99.2), respectively, with 95.6% PPV and 93.8% NPV. The PPV rapidly improved with increasing disease prevalence from 19.8% to 96.1% in the presence of either IgM or IgG, while the NPV remained high with a change from 99.9% to 93.1%. The area under the ROC curve was 0.945 (95% CI: 0.903-0.988) for subjects with either IgM or IgG positivity. In conclusion, the immunochromatography-based COVID-19 IgG/IgM rapid test is a useful and practical diagnostic assay for detection of COVID-19, especially in the presence of IgM or IgG antibodies.

Keywords: COVID-19; coronavirus; immunochromatography; real-time polymerase chain reaction.

Figure 1

Estimated changes in PPV and NPV for IgM/IgG positivity according to disease prevalence by immunochromatography assay. A, PPV in either IgM or IgG positive group, (B) NPV in either IgM or IgG positive group Data were described as mean ± standard deviation. IgG, immunoglobulin G; IgM, immunoglobulin M; NPV, negative predictive value; PPV, positive predictive value

Figure 2

ROC curve of immunochromatography‐based IgM/IgG rapid assay for COVID‐19. The dashed line for either IgM or IgG positivity and solid line for both IgM and IgG positivity are presented in the ROC curve. COVID‐19, coronavirus disease 2019; IgG, immunoglobulin G; IgM, immunoglobulin M; ROC, receiver operating characteristic