TTV detection and quantification.
TTV DNA was quantified in nasopharyngeal swabbing samples used for
SARS-Cov-2 RT-PCR. DNA was extracted using the QiaSymphony instrument
(Qiagen, Hilden, Germany) from 200 µl of Universal Transport Medium.
Quantification was carried out by real-time PCR (TTV R-Gene, bioMérieux,
Marcy l’étoile, France) on an ABI 7500 instrument (ThermoFisher,
Waltham, MA) according to manufacturer instructions. The limit of
quantification is 250 copies per mL.