Analytic Sensitivity of 3 Nucleic Acid Detection Assays in Diagnosis of SARS-CoV-2 Infection. (27th November 2020)

• Record Type: Journal Article
• Authors: Sieker, Jakob T; Horowitz, Coby; Hu, Cheng-Tsung K; Lacombe-Daphnis, Meriane; Chirokas, Bernadette; Pina, Coteia; Heger, Nicholas E; Rabson, Arthur R; Zhou, Ming; Bogen, Steven A; Horowitz, Gary L
• Is Part Of: Journal of applied laboratory medicine. Volume 6:Number 2(2021)
• Page Start: 421
• Page End: 428
• Publication Date: 2020-11-27
• Subjects: Clinical chemistry -- Periodicals; Diagnosis, Laboratory -- Periodicals; 616.0756
• DOI: 10.1093/jalm/jfaa187
• Languages: English
• ISSNs: 2576-9456

Abstract

Abstract: Background: Detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) by reverse transcription PCR is the primary method to diagnose coronavirus disease 2019 (COVID-19). However, the analytic sensitivity required is not well defined and it is unclear how available assays compare. Methods: For the Abbott RealTime SARS-CoV-2 assay (m2000; Abbott Molecular), we determined that it could detect viral concentrations as low as 26 copies/mL, we defined the relationship between cycle number and viral concentrations, and we tested naso- and oropharyngeal swab specimens from 8538 consecutive individuals. Using the m2000 as a reference assay method, we described the distribution of viral concentrations in these patients. We then used selected clinical specimens to determine the positive percent agreement of 2 other assays with more rapid turnaround times [Cepheid Xpert Xpress (GeneXpert; Cepheid); n = 27] and a laboratory developed test on the Luminex ARIES system [ARIES LDT (Luminex); n = 50] as a function of virus concentrations, from which we projected their false-negative rates in our patient population. Results: SARS-CoV-2 was detected in 27% (95% CI: 26%–28%) of all specimens. Estimated viral concentrations were widely distributed, and 17% (95% CI: 16%–19%) of positive individuals had viral concentrations <845 copies/mL. Positive percent agreement was strongly related to viral concentration, and reliable detection (i.e., ≥95%) was observed at concentrations >100 copies/mL for the GeneXpert but not the ARIES LDT, corresponding to projected false-negative rates of 4% (95% CI: 0%–21%) and 27% (95% CI: 11%–46%), respectively. Conclusions: Substantial proportions of clinical specimens have low to moderate viral concentrations and may be missed by methods with less analytic sensitivity.