This suggests that sensitivity increased with time from disease onset; thus, antibody testing is not a useful diagnostic tool during the early stages of the disease. antibody and RT-PCR tests was 7 days. Characteristics of four patients with COVID-19 with negative results for both rapid antigen and IgG antibody assays Four patients (0.4%) had positive RT-PCR test results despite negative results of both rapid antigen test and IgG antibody tests. These patients had a history of close contact with patients with COVID-19 who were family Velpatasvir members, coresidents, or caregivers. In addition, all patients had fever, respiratory symptoms, and other clinical symptoms suggestive of COVID-19. The characteristics of these patients are presented in Table 5. Table 5 Characteristics of four patients with COVID-19 with negative antigen and antibody results.
1 86M+++4 2 92F+?+1 3 87M+++3 4 78M+++8 Open in a separate window COVID-19, coronavirus disease 2019; ED, emergency department. Discussion In this study, we examined the diagnostic accuracy of a combination of rapid antigen and IgG antibody tests using RT-PCR as the gold standard. The sensitivity, specificity, PPV, Velpatasvir NPV, and AUC of rapid antigen tests were higher than those of IgG antibody tests. There are few reports on the use of antibody tests for diagnosis in the acute phase of the disease [12]. Moreover, the accuracy of this antibody test used in the present study was not sufficient for it to be the sole diagnostic tool. However, the diagnostic accuracy greatly improved when rapid antigen testing was combined with IgG antibody testing. A Cochrane systematic review and meta-analysis in 2021 reported a sensitivity of 68.9% (95% CI: 61.8C75.1) and a specificity of 99.6% (95% CI: 99.0C99.8) for rapid antigen testing [11]. The sensitivity was 78.3% (95% CI: 71.1C84.1) when used during the first 7 days of symptoms. However, this sensitivity decreased to 51.0% (95% CI: 40.8C61.0) during the second week of symptoms [11]. Considering that approximately half Velpatasvir the patients in this study had symptom onset Rabbit Polyclonal to SYT13 within 7 days, and the median number of days since symptom onset in positive patients was 5 days. The sensitivity of rapid antigen testing (73.7%) in this study is consistent with the results of previous studies. Antibody testing was also studied in 2020 [12]. Furthermore, the sensitivities of IgG were found to be 29.7% (95% CI: 22.1C38.6), 66.5% (95% CI: 57.9C74.2), and 88.2% (95% CI: 83.5C91.8) in the first, second, and third week, respectively. This suggests that sensitivity increased with time from disease onset; thus, antibody testing is not a useful diagnostic tool during the early stages of the disease. Similarly, the sensitivities of IgM were 23.2% (95% CI: 14.9C34.2), 58.4% (95% CI: 45.5C70.3), and Velpatasvir 75.4% (95% CI: 64.3C83.8) during the first, second, and third weeks, respectively. In addition, the sensitivities of IgA were 28.4% (95% CI: 0.9C94.3), 78.1% (95% CI: 9.5C99.2), and 98.7% (95% CI: 39.0C100) during the same three weeks, respectively. Furthermore, the sensitivities of combination of IgG/IgM were 30.1% (95% CI: 21.4C40.7), 72.2% (95% CI: 63.5C79.5), and 91.4% (95% CI: 87.0C94.4) during these same three weeks, respectively. Therefore, the sensitivity of all antibody levels was low within the first week of disease onset [12], and it is unclear whether IgG, IgM, IgA, and IgG/IgM antibodies are preferable for diagnosing acute infection. After the third week, the sensitivity of IgG was 80.3% (95% CI: 72.4C86.4) and of IgM was 68.1% (95% CI: 55.0C78.9). This indicated that if either IgG or IgM was positive, its sensitivity was.
