Journal of Clinical Virology

SARS-CoV-2 serology

In response to the COVID-19 pandemic, commercial molecular assays for SARS-CoV-2 testing have been rapidly developed and broadly deployed in laboratories worldwide. Although these assays have been reported to correlate well, we sought to compare the Xpert® Xpress SARS-CoV-2 to the cobas® SARS-CoV-2 or the Lightmix® Modular SARS and Wuhan CoV E-gene assay for nasopharyngeal (NP) swabs with low levels of SARS-CoV-2 RNA. Thirty-seven NP swabs were studied, including 10 samples with a moderate cycle threshold (Ct) between 30-33.9, and 22 with Ct≥34, and 5 negative for SARS-CoV-2. Overall concordance on initial comparison was 86.5% (32/37), which was 100% concordance for samples with Ct values ranging between 30-33.9. Discordance amongst samples showing a Ct ≥34 was 22.7% (5/22). Endpoint value analysis on the Xpress SARS-CoV-2 within the discordant samples noted two with an endpoint value >5, which were detected by the cobas® or Lightmix®. Testing of SARS-CoV-2 on the three commercial assays was comparable for NP swabs with moderate Ct values, while high Ct values were less concordant. Importantly, analysis of Xpert® endpoint values improved interpretation of discrepant results.

The following files describe the information collected from each patients and how to obtain the stool sample.

Demonstration of the diagnostic agreement of capillary and venous blood samples, using Hepatitis-C Virus SD Bioline© Rapid Test: A clinic-based study in Cambodia Clinic base study to assess capillary and venipuncture specimens agreement.Two independent, blinded readers, and in the case of disagreement, a third reader, interpreted the results of each blood sample. Discrepant sample pairs were tested with an enzyme immunoassay, the reference standard, at the Institute Pasteur of Cambodia. 421 pairs of samples were collected. Results and study data have been collected using REDCap electronic data capture tools hosted at MSF-Epicentre