| Author/Editor | Kogoj, Rok; Korva, Miša; Knap, Nataša; Resman Rus, Katarina; Pozvek, Patricija; Avšič-Županc, Tatjana; Poljak, Mario | |
| Title | Comparative evaluation of six SARS-CoV-2 real-time RT-PCR diagnostic approaches shows substantial genomic variant‐dependent intra- and inter-test variability, poor interchangeability of cycle threshold and complementary turn-around times | |
| Type | članek | |
| Vol. and No. | Letnik 11, št. 4 | |
| Publication year | 2022 | |
| Volume | str. 1-14 | |
| ISSN | 2076-0817 - Pathogens | |
| Language | eng | |
| Abstract | Several professional societies advise against using real-time Reverse-Transcription PCR (rtRT-PCR) cycle threshold (Ct) values to guide clinical decisions. We comparatively assessed the variability of Ct values generated by six diagnostic approaches by testing serial dilutions of well-characterized isolates of 10 clinically most relevant SARS-CoV-2 genomic variants: Alpha, Beta, Gamma, Delta, Eta, Iota, Omicron, A.27, B.1.258.17, and B.1 with D614G mutation. Comparison of three fully automated rtRT-PCR analyzers and a reference manual rtRT-PCR assay using RNA isolated with three different nucleic acid isolation instruments showed substantial inter-variant intra-test and intra-variant inter-test variability. Ct value differences were dependent on both the rtRT-PCR platform and SARS-CoV-2 genomic variant. Differences ranging from 2.0 to 8.4 Ct values were observed when testing equal concentrations of different SARS-CoV-2 variants. Results confirm that Ct values are an unreliable surrogate for viral load and should not be used as a proxy of infectivity and transmissibility, especially when different rtRT-PCR assays are used in parallel and multiple SARS-CoV-2 variants are circulating. A detailed turn-around time (TAT) comparative assessment showed substantially different TATs, but parallel use of different diagnostic approaches was beneficial and complementary, allowing release of results for more than 81% of non-priority samples within 8 h after admission. | |
| Keywords | SARS-CoV-2 COVID-19 genomska varianta SARS-CoV-2 COVID-19 genomic variant |