Interpretation of single target positivity among SARS-CoV-2 RT-PCR result tests
Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged and is responsible for coronavirus disease 19 (COVID-19). Diagnostic tests have been developed, mainly based on reverse-transcriptase PCR (RT-PCR). Most RT-PCR assays target at least two SARS-CoV-2 genes. In some cases, only one target gene is detected; the interpretation of such cases remains unclear. Objectives: Our objective was to analyse one target positive (OPT) RT-PCR results, using two RT-PCR assays: the Xpert® Xpress SARS-CoV-2 (Cepheid diagnosis, "Cepheid") and the Cobas® 6800 SARS-CoV-2 Test (Roche Molecular Diagnostics, "Roche"). Methods: All SARS-CoV-2 RT-PCR results performed on respiratory samples with the Roche or the Cepheid tests, from 23rd March to 6th August 2020 were collected. A patient with an OPT result was classified as "probable COVID-19" if they met at least one of the three following criteria: (i) history of a two gene-positive SARS-CoV-2 RT-PCR result, (ii) anti-SARS-CoV-2 antibody (IgG) detection or (iii) compatible chest computed tomography scan (CT-scan). Results: A total of 18,630 and 1189 SARS-CoV-2 RT-PCR tests were performed with the Roche and Cepheid tests, respectively. Among the positive SARS-CoV-2 RT-PCR, 293 samples - corresponding to 264 patients - were OPT (11% of the positive samples). Of these patients, 180 (68%) had at least one of the three criteria listed above and were classified as probable COVID-19. Conclusions: Sixty-eight percent of the patients with an OPT result were classified as probable COVID-19 and are probably at a late stage of infection. Serology and imaging can be helpful to confirm diagnosis.
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BibTeX
@article{fenaux2026interpretation,
title = {{Interpretation of single target positivity among SARS-CoV-2 RT-PCR result tests}},
author = {Honorine Fenaux and Théo Ghelfenstein-Ferreira and Maud Salmona and Nadia Mahjoub and Linda Feghoul and Sarah Maylin and Marie-Laure Chaix and Marine Minier and Audrey Gabassi and Jérôme Le Goff and Constance Delaugerre},
journal = {Journal of Clinical Virology Plus},
year = {2026},
month = oct,
doi = {10.1016/j.jcvp.2021.100021},
url = {https://hal.science/hal-05783324v1},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Interpretation of single target positivity among SARS-CoV-2 RT-PCR result tests
AU - Honorine Fenaux
AU - Théo Ghelfenstein-Ferreira
AU - Maud Salmona
AU - Nadia Mahjoub
AU - Linda Feghoul
AU - Sarah Maylin
AU - Marie-Laure Chaix
AU - Marine Minier
AU - Audrey Gabassi
AU - Jérôme Le Goff
AU - Constance Delaugerre
PY - 2026
DA - 2026/10/07
JO - Journal of Clinical Virology Plus
DO - 10.1016/j.jcvp.2021.100021
UR - https://hal.science/hal-05783324v1
AB - Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged and is responsible for coronavirus disease 19 (COVID-19). Diagnostic tests have been developed, mainly based on reverse-transcriptase PCR (RT-PCR). Most RT-PCR assays target at least two SARS-CoV-2 genes. In some cases, only one target gene is detected; the interpretation of such cases remains unclear. Objectives: Our objective was to analyse one target positive (OPT) RT-PCR results, using two RT-PCR assays: the Xpert® Xpress SARS-CoV-2 (Cepheid diagnosis, "Cepheid") and the Cobas® 6800 SARS-CoV-2 Test (Roche Molecular Diagnostics, "Roche"). Methods: All SARS-CoV-2 RT-PCR results performed on respiratory samples with the Roche or the Cepheid tests, from 23rd March to 6th August 2020 were collected. A patient with an OPT result was classified as "probable COVID-19" if they met at least one of the three following criteria: (i) history of a two gene-positive SARS-CoV-2 RT-PCR result, (ii) anti-SARS-CoV-2 antibody (IgG) detection or (iii) compatible chest computed tomography scan (CT-scan). Results: A total of 18,630 and 1189 SARS-CoV-2 RT-PCR tests were performed with the Roche and Cepheid tests, respectively. Among the positive SARS-CoV-2 RT-PCR, 293 samples - corresponding to 264 patients - were OPT (11% of the positive samples). Of these patients, 180 (68%) had at least one of the three criteria listed above and were classified as probable COVID-19. Conclusions: Sixty-eight percent of the patients with an OPT result were classified as probable COVID-19 and are probably at a late stage of infection. Serology and imaging can be helpful to confirm diagnosis.
SN - 2667-0380
SN - 2667-0380
ER -