Utility of Stool PCR for the Diagnosis of COVID-19: Comparison of Two Commercial Platforms.
J Clin Microbiol
; 58(9)2020 08 24.
Article
in English
| MEDLINE | ID: covidwho-628838
ABSTRACT
The ability to detect SARS-CoV-2 in the upper respiratory tract ceases after 2 to 3 weeks post-symptom-onset in most patients. In contrast, SARS-CoV-2 can be detected in the stool of some patients for greater than 4 weeks, suggesting that stool may hold utility as an additional source for diagnosis. We validated the Cepheid Xpert Xpress SARS-CoV-2 and Hologic Panther Fusion real-time RT-PCR assays for detection of viral RNA in stool specimens and compared performance. We utilized remnant stool specimens (n = 79) from 77 patients with gastrointestinal symptoms. Forty-eight patients had PCR-confirmed COVID-19, and 29 either were nasopharyngeal/oropharyngeal PCR negative or presented for reasons unrelated to COVID-19 and were not tested. Positive percent agreement between the Cepheid and Hologic assays was 93% (95% confidence interval [CI] 81.1% to 98.2%), and negative percent agreement was 96% (95% CI 89% to 0.99%). Four discrepant specimens (Cepheid positive only, n = 2; Hologic positive only, n = 2) exhibited average cycle threshold (CT ) values of >37 for the targets detected. Of the 48 patients with PCR-confirmed COVID-19, 23 were positive by both assays (47.9%). For the negative patient group, 2/29 were positive by both assays (6.9%). The two stool PCR-positive, nasopharyngeal/oropharyngeal PCR-negative patients were SARS-CoV-2 IgG positive. Our results demonstrate acceptable agreement between two commercially available molecular assays and support the use of stool PCR to confirm diagnosis when SARS-CoV-2 is undetectable in the upper respiratory tract.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Pneumonia, Viral
/
Polymerase Chain Reaction
/
Coronavirus Infections
/
Clinical Laboratory Techniques
/
Feces
/
Betacoronavirus
Type of study:
Diagnostic study
/
Prognostic study
Topics:
Vaccines
Limits:
Humans
Language:
English
Year:
2020
Document Type:
Article
Affiliation country:
Jcm.01369-20
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