tetano
Editor, Senior Moderator
J Appl Lab Med
. 2021 Mar 1;6(2):421-428.
doi: 10.1093/jalm/jfaa187.
Analytic Sensitivity of 3 Nucleic Acid Detection Assays in Diagnosis of SARS-CoV-2 Infection
Jakob T Sieker[SUP] 1 [/SUP], Coby Horowitz[SUP] 1 [/SUP], Cheng-Tsung K Hu[SUP] 1 [/SUP], Meriane Lacombe-Daphnis[SUP] 1 [/SUP], Bernadette Chirokas[SUP] 1 [/SUP], Coteia Pina[SUP] 1 [/SUP], Nicholas E Heger[SUP] 1 [/SUP], Arthur R Rabson[SUP] 1 [/SUP], Ming Zhou[SUP] 1 [/SUP], Steven A Bogen[SUP] 1 [/SUP], Gary L Horowitz[SUP] 1 [/SUP]
Affiliations
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.
. 2021 Mar 1;6(2):421-428.
doi: 10.1093/jalm/jfaa187.
Analytic Sensitivity of 3 Nucleic Acid Detection Assays in Diagnosis of SARS-CoV-2 Infection
Jakob T Sieker[SUP] 1 [/SUP], Coby Horowitz[SUP] 1 [/SUP], Cheng-Tsung K Hu[SUP] 1 [/SUP], Meriane Lacombe-Daphnis[SUP] 1 [/SUP], Bernadette Chirokas[SUP] 1 [/SUP], Coteia Pina[SUP] 1 [/SUP], Nicholas E Heger[SUP] 1 [/SUP], Arthur R Rabson[SUP] 1 [/SUP], Ming Zhou[SUP] 1 [/SUP], Steven A Bogen[SUP] 1 [/SUP], Gary L Horowitz[SUP] 1 [/SUP]
Affiliations
- PMID: 33674879
- DOI: 10.1093/jalm/jfaa187
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.