Overcoming limitations in the availability of swabs systems used for SARS-CoV-2 laboratory diagnostics

The diagnosis of COVID-19 relies on the direct detection of SARS-CoV-2 RNA in respiratory specimens by RT-PCR. The pandemic spread of the disease caused an imbalance between demand and supply of materials and reagents needed for diagnostic purposes including swab sets. In a comparative effectiveness study, we conducted serial follow-up swabs in hospitalized laboratory-confirmed COVID-19 patients. We assessed the diagnostic performance of an in-house system developed according to recommendations by the US CDC. In a total of 96 serial swabs, we found significant differences in the accuracy of the different swab systems to generate a positive result in SARS-CoV-2 RT-PCR, ranging from around 50 to 80%. Of note, an in-house swab system was superior to most commercially available sets as reflected by significantly lower Ct values of viral genes. Thus, a simple combination of broadly available materials may enable diagnostic laboratories to bypass global limitations in the supply of swab sets.

Automated summary

The study evaluated the performance of different swab systems in COVID-19 diagnosis through serial swab testing, with findings indicating that in-house swab systems outperformed commercially available sets. This suggests that a simple combination of widely available materials could help diagnostic laboratories overcome global limitations in the supply of swab sets.