Validation of a SARS-CoV-2 RT-PCR assay: a requirement to evaluate viral contamination in human semen

RESEARCH QUESTION: Is it possible to validate an accurate and reliable method for direct detection of SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR) in human semen fractions? DESIGN: This qualitative improvement study aimed to provide a prospective validation of SARS-CoV-2 detection in male semen. The SARS-CoV-2 genome was detected by multiplex real-time RT-PCR on patient samples that underwent routine semen analyses for infertility at the Center for Reproductive Medicine at the University Hospital of Clermont-Ferrand. Samples comprised surplus semen collected for treatment with assisted reproductive technology. Seminal fluid and spermatozoa fractions were isolated with density gradient centrifugation and cryopreserved. Positive samples were prepared with a standard of inactivated SARS-CoV-2 particles. RESULTS: The analytical method was validated in both seminal fluid and spermatozoa fractions. In both semen fractions, the assay was repeatable, reproducible and showed high sensitivity with a limit of detection of 0.33 SARS-CoV-2 genome copies/µl. The limit of quantification was 1 copy of the SARS-CoV-2 genome/µl. The method was effective regardless of semen quality (normal and altered sperm parameters), number of spermatozoa or the cryoprotectant media used to freeze spermatozoa. CONCLUSION: This validated RT-PCR assay provided accurate and reliable screening of SARS-CoV-2 in seminal fluid and spermatozoa fractions. This method is essential to ensure protection against viral contamination in the cryobanking process.