Current best evidence for clinical care (more info)
Purpose: Rapid severe acute respiratory syndrome coronavirus 2 test kits are crucial for bridging diagnostic gaps in health facilities and community screening mainly in resource limited settings. However, there is no objective evidence on their diagnostic performance. Thus, the study aimed to evaluate comparative diagnostic performance of three selected SARS-CoV-2 IgG/IgM rapid test kits in Ethiopia.
Methods: A cross-sectional study was conducted among 200 clients between May and July 2020 in Addis Ababa, Ethiopia. The performance of three SARS-CoV-2 rapid test kits EGENE, CTK BIOTECKs Onsite, and ACON Biotech were evaluated using blood specimens against RT-PCR on respiratory swabs. Sensitivity, specificity, and agreement with each other and to RT-PCR were computed using Vassarstats, MedCalc and SPSS version 23 statistical software.
Results: Test kits showed a heterogeneous comparative diagnostic performance in their sensitivity and specificity. The sensitivity was 61.18% (95% CI: 49.96-71.37%), 74.12% (95% CI: 63.28-82.74%) and 83.53% (95% CI: 73.57-90.38%) for kit A, B and C, respectively. Similarly, the specificity was 96.52% (90.81-98.88%), 94.78% (88.52-97.86%) and 94.78% (88.52-97.86%) for test kit A, B and C, respectively. The test kits have an agreement with RT-PCR with kappa value of 0.60 (0.48-0.83), 0.71 (0.65-0.93), and 0.80 (0.76-1.04) for A, B, and C, respectively. There was a significant difference on diagnostic performance among the three test kits and PCR with a p-value < 0.001 Cochran's Q test.
Conclusion: The diagnostic performance of the test kits was promising and recommended for COVID-19 diagnostics in combination with RT-PCR to detect more infected patients. It allows determining the seroprevalence of the virus and true extent of SARS-COV-2 community spread in resource limited settings. We underline countries to evaluate rapid diagnostic test kits before diagnostic use.
|Discipline / Specialty Area||Score|
|Pediatric Hospital Medicine||
|Pediatric Emergency Medicine||
Knowing the accuracy of rapid tests for Covid-19, their limitations and usefulness are really important for places with low technological and economic resources.
Rapid development of severe acute respiratory syndrome coronavirus test kits is important rapid identification of patients. This study evaluated the comparative diagnostic performance of three commercially available SARS-CoV-2 rapid IgG/IgM assays. This demonstrates heterogeneous comparative diagnostic performance. This study shows a higher sensitivity than prior studies. In resource limited settings, this test kit can be helpful to determine the sero-prevalence of the virus and true extent of SARS-COV-2 community spread.
It appears that test kit C (Acon Biotech) has the highest likelihood ratio among the three kits compared in the particular setting.
As a practicing Hospitalist with an interest in antibody testing in COVID-19, I find this small study doesn't help in providing care to COVID-19 patients. Antibody testing, outside of convalescent donor screening is not very helpful. Using simultaneous RtPCR as a gold standard is not helpful as antibodies take several days to weeks to form. Patients with negative PCR could have had prior infection, and patients with recent infection could have negative antibodies. The fact that the sensitivity is best at two weeks from symptoms is no surprise. It is of little clinical help since patients are typically no longer infectious at that point. There is at least one antibody test that has been pulled from the market in the US due to poor performance. Antibody testing is rarely helpful in the acute management of COVID-19.