Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Is Comparable in Clinical Samples Preserved in Saline or Viral Transport Medium.
Author(s): Radbel J, Jagpal S, Roy J, Brooks A, Tischfield J, Sheldon M, Bixby C, Witt D, Gennaro ML, Horton DB, Barrett ES, Carson JL, Panettieri RA Jr, Blaser MJ
Publication: J Mol Diagn, 2020, Vol. 22, Page 871-875
PubMed ID: 32405270 PubMed Review Paper? No
Purpose of Paper
This paper compared the detection of SARS-CoV-2, the virus that causes the novel 2019 coronavirus disease (COVID, COVID-19, COVID19) viral RNA in respiratory swab specimens stored for up to 18 h at room temperature in phosphate-buffered saline (PBS) with those stored in viral transport medium.
Conclusion of Paper
Intra-patient variability was low with strong correlation of cycle threshold (CT) values between replicates for each of the three genes examined. CT values were strongly correlated for the three genes, regardless of transport medium or storage duration.
Studies
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Study Purpose
This study compared the detection of SARS-CoV-2 RNA in respiratory swab specimens stored for up to 18 h at room temperature in phosphate-buffered saline (PBS) with those stored in viral transport medium. Respiratory secretions from 16 subjects mechanically ventilated for acute hypoxemic respiratory failure due to confirmed COVID-19 pneumonia were collected over a 4-day period into a sterile container via closed-circuit, in-line catheter suction of respiratory secretions from the endotracheal tube. Swabs of respiratory secretions were obtained and placed in transport tubes containing PBS or viral transport medium and processed immediately or after storage for 2, 4, 6, or 18 h at room temperature. To assess intra-patient reliability, matched-pair swab specimens were collected from two individuals, stored in PBS (n=10) or viral transport medium (n=9), and processed immediately. RNA was extracted in an automated system using the Viral DNA/RNA 300 Kit. Detection of the SARS-CoV-2 ORF1ab, S, and N genes was performed by real-time qRT-PCR.
Summary of Findings:
CT values were significantly below the cutoff threshold (CT<37) for all specimens. Intra-patient variability was low with strong correlation of CT values between the replicates in each gene assay. The correlations between matched specimens stored in PBS and those stored in viral transport medium were significant for all three genes examined 0.93 for N gene, 0.83 for ORF1ab gene, and 0.91 for the S gene (P<0.05, all). In addition, CT values were not affected by storage at room temperature for up to 18 h for any of the three genes examined, regardless of storage medium.
Biospecimens
Preservative Types
- None (Fresh)
Diagnoses:
- Pneumonia/Respiratory Infection
Platform:
Analyte Technology Platform RNA Real-time qRT-PCR Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Storage Short-term storage solution Viral Transport Medium
Phosphate-buffered saline
Real-time qRT-PCR Specific Targeted nucleic acid SARS-CoV-2 ORF1ab gene
SARS-CoV-2 S gene
SARS-CoV-2 N gene
Storage Time at room temperature 0 h
2 h
4 h
6 h
18 h