Detection of SARS-CoV-2 RNA in nasopharyngeal swabs from COVID-19 patients and asymptomatic cases of infection by real-time and digital PCR.
Klin Lab Diagn
; 65(12): 785-792, 2020 Dec 29.
Article
in English
| MEDLINE | ID: covidwho-1000747
ABSTRACT
In this work we tested two reagent kits developed by us for detecting SARS-CoV-2 RNA using a fragment of the ORF1ab gene in digital PCR and real-time PCR formats. Data were obtained on the detection of SARS-CoV-2 virus RNA in nasopharyngeal swabs of patients with COVID-19 and asymptomatic carriers. The developed reagent kits provided 100% sensitivity and a detection limit of 103 GE / ml for qPCR, and at least 200 copies / ml of viral RNA when performing digital PCR. These methods were tested using a panel of 1,328 samples collected from patients with suspected COVID-19 at the beginning of 2020 in the Russian Federation. It has been shown that dPCR is more sensitive and can be used to analyze samples with low viral load, including those from patients without clinical symptoms. dPCR significantly improves the accuracy of laboratory research and significantly reduces the number of false negative results in the diagnosis of SARS-CoV-2. Determination of the concentration of SARS-CoV-2 RNA in patients with different clinical course of the disease showed that the concentration of viral RNA can sharply decrease in the first days of the disease. A low concentration of viral RNA in samples from patients is also characteristic of asymptomatic disease. Digital PCR provides a higher detection rate for asymptomatic cases, which is approximately 75% of those infected, as opposed to 45% for real-time PCR. The results obtained on the use of the digital PCR method for detecting SARS-CoV-2 RNA showed that this method is especially suitable for detecting RNA in case of its low concentration in contacts, as well as for monitoring changes in viral load in convalescent patients.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
RNA, Viral
/
Nasopharynx
/
Asymptomatic Infections
/
SARS-CoV-2
/
COVID-19
Type of study:
Diagnostic study
/
Prognostic study
Limits:
Humans
Country/Region as subject:
Asia
/
Europa
Language:
English
Journal:
Klin Lab Diagn
Journal subject:
Laboratory Techniques and procedures
Year:
2020
Document Type:
Article
Similar
MEDLINE
...
LILACS
LIS