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Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients.
Am J Clin Pathol. 2020 09 08; 154(4):479-485.AJ

Abstract

OBJECTIVES

We examined the distribution of reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (CT) values obtained from symptomatic patients being evaluated for coronavirus disease 2019 (COVID-19) to determine the proportion of specimens containing a viral load near the assay limit of detection (LoD) to gain practical insight to the risk of false-negative results. We also examined the relationship between CT value and patient age to determine any age-dependent difference in viral load or test sensitivity.

METHODS

We collected CT values obtained from the cobas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay corresponding to 1,213 combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals that were reported as positive or presumptive positive for SARS-CoV-2. CT values were stratified by SARS-CoV target and patient age group.

RESULTS

In total, 93.3% to 98.4% of specimens demonstrated CT values greater than 3× the assay LoD, at which point false-negative results would not be expected. The mean of CT values between age groups was statistically equivalent with the exception of patients in age group 80 to 89 years, which demonstrated slightly lower CTs.

CONCLUSIONS

Based on the distribution of observed CT values, including the small proportion of specimens with values near the assay LoD, there is a low risk of false-negative RT-PCR results in combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals.

Authors+Show Affiliations

Department of Pathology, The Medical College of Wisconsin, Milwaukee.Department of Microbiology and Molecular Diagnostics, Wisconsin Diagnostic Laboratories, Milwaukee.School of Medicine, The Medical College of Wisconsin, Milwaukee.School of Medicine, The Medical College of Wisconsin, Milwaukee.Department of Pathology, The Medical College of Wisconsin, Milwaukee.Department of Internal Medicine, Division of Infectious Disease, The Medical College of Wisconsin, Milwaukee.Department of Pathology, The Medical College of Wisconsin, Milwaukee.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32687186

Citation

Buchan, Blake W., et al. "Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients." American Journal of Clinical Pathology, vol. 154, no. 4, 2020, pp. 479-485.
Buchan BW, Hoff JS, Gmehlin CG, et al. Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients. Am J Clin Pathol. 2020;154(4):479-485.
Buchan, B. W., Hoff, J. S., Gmehlin, C. G., Perez, A., Faron, M. L., Munoz-Price, L. S., & Ledeboer, N. A. (2020). Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients. American Journal of Clinical Pathology, 154(4), 479-485. https://doi.org/10.1093/ajcp/aqaa133
Buchan BW, et al. Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients. Am J Clin Pathol. 2020 09 8;154(4):479-485. PubMed PMID: 32687186.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Distribution of SARS-CoV-2 PCR Cycle Threshold Values Provide Practical Insight Into Overall and Target-Specific Sensitivity Among Symptomatic Patients. AU - Buchan,Blake W, AU - Hoff,Jessica S, AU - Gmehlin,Cameron G, AU - Perez,Adriana, AU - Faron,Matthew L, AU - Munoz-Price,L Silvia, AU - Ledeboer,Nathan A, PY - 2020/7/21/pubmed PY - 2020/9/18/medline PY - 2020/7/21/entrez KW - COVID-19 KW - Coronavirus KW - Cycle threshold KW - RT-PCR KW - SARS-CoV-2 KW - Viral load SP - 479 EP - 485 JF - American journal of clinical pathology JO - Am. J. Clin. Pathol. VL - 154 IS - 4 N2 - OBJECTIVES: We examined the distribution of reverse transcription polymerase chain reaction (RT-PCR) cycle threshold (CT) values obtained from symptomatic patients being evaluated for coronavirus disease 2019 (COVID-19) to determine the proportion of specimens containing a viral load near the assay limit of detection (LoD) to gain practical insight to the risk of false-negative results. We also examined the relationship between CT value and patient age to determine any age-dependent difference in viral load or test sensitivity. METHODS: We collected CT values obtained from the cobas severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) assay corresponding to 1,213 combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals that were reported as positive or presumptive positive for SARS-CoV-2. CT values were stratified by SARS-CoV target and patient age group. RESULTS: In total, 93.3% to 98.4% of specimens demonstrated CT values greater than 3× the assay LoD, at which point false-negative results would not be expected. The mean of CT values between age groups was statistically equivalent with the exception of patients in age group 80 to 89 years, which demonstrated slightly lower CTs. CONCLUSIONS: Based on the distribution of observed CT values, including the small proportion of specimens with values near the assay LoD, there is a low risk of false-negative RT-PCR results in combined nasopharyngeal-oropharyngeal specimens obtained from symptomatic individuals. SN - 1943-7722 UR - https://www.unboundmedicine.com/medline/citation/32687186/Distribution_of_SARS_CoV_2_PCR_Cycle_Threshold_Values_Provide_Practical_Insight_Into_Overall_and_Target_Specific_Sensitivity_Among_Symptomatic_Patients_ L2 - https://academic.oup.com/ajcp/article-lookup/doi/10.1093/ajcp/aqaa133 DB - PRIME DP - Unbound Medicine ER -