RESUMEN
To evaluate the effect of colloidal gold immunochromatographic assay (GCIA) combined with chemiluminescent immunoassay (CLIA) in reducing the false positive of antibodies against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2). Thirty-three serum samples from 19 patients with SARS-CoV-2 infection at different times, and 55 serum samples from 55 patients not infected with SARS-CoV-2. but infected instead with other pathogens or suffering from autoimmune diseases were collected from the Affiliated Hospital of North Sichuan Medical College and Nanchong Central Hospital from 22 January to 5 March 2020. Serum IgM and IgG against SARS-CoV-2 were detected by GICA and CLIA respectively, and the results were analyzed. The sensitivity of GCIA for detection of IgM and IgG against SARS - CoV - 2 was 100.0% and 94.74%. respectively, values that were similar with those for CLIA (92.86% and 100.0%) (P = 1.000). The specificity of GCIA for IgM and IgG against SARS-CoV-2 was 70.91% and 74.55% respectively, which was significantly lower than that of CLIA (98.18% and 89.09%) (P < 0.01). The results of IgM and IgG against SARS-CoV-2 detected by the two methods were consistent (P=0.000) . and their Kappa was 0.434 and 0.406. respectively. Analyses of ROC curves showed that the AUC of IgM and IgG against SARS-CoV-2 detected by GCIA was 0.855 and 0.846. respectively, which was significantly lower than that of CLIA (0.955 and 0.945, respectively) (PC0.05). The sensitivity of combined detection of IgM and IgG against SARS -CoV-2 was 92.86% and 94.74%. and the specificity was 100.0% and 100.0%, respectively. Analyses of ROC curves showed that the AUC of combined detection of IgM and IgG against SARS-CoV-2 was 0.964 and 0.974. respectively, which was higher titan that of each method alone. GCIA combined with CLIA can improve the specificity of detection of IgM and IgG against SARS-CoV-2, which may merit clinical application.