Validity of the Rapid Nasopharyngeal Antigen Swab for the Detection of SARS-CoV-2 on Cadavers

Background: SARS-CoV-2 is classified as a class 3 biological agent; therefore, autopsies on positive subjects must be performed in BSL 3 sectorial rooms. However, many centers lacking such facilities perform molecular nasopharyngeal swabs for SARS-CoV-2 on corpses before autopsy. This approach, though, is marked by prolonged reporting times and extremely high costs. This study aims to compare the results of molecular swabs (RT-PCR) with rapid antigen swabs (RAT) in order to assess if RAT can serve as the sole test for determining corpse positivity or negativity. Methods: Sixty corpses with positive molecular nasopharyngeal swabs for SARS-CoV-2, performed either ante-mortem or post-mortem, were selected. Afterward, they underwent rapid antigen swabs within 0 to 11 days after the last molecular exam. Results: Out of 60 corpses with positive molecular swabs, 52 antigen swabs were positive (86.67%), and 8 were negative (13.33%), indicating a sensitivity of 86.66% and specificity of 100%. Conclusions: Considering the sensitivity and specificity values observed in this study, RAT could be used as the primary investigation on corpses, especially in centers that lack BSL 3 sectorial rooms. Molecular swabs could then serve as a secondary test for subjects negative on RAT.