Identification of contagious SARS-CoV-2 infected individuals by Roche's Rapid Antigen Test.
Clin Chem Lab Med
; 60(5): 778-785, 2022 04 26.
Article
in English
| MEDLINE | ID: covidwho-1731617
ABSTRACT
OBJECTIVES:
Rapid antigen tests (RAT) can provide valuable information on the presence or absence SARS-CoV-2 within 15 min without the need of a laboratory. The analytical and diagnostic characteristics of available RATs has led to the question whether they can safely distinguish between infectious and non-infectious patients in an acute care setting.METHODS:
Three nasopharyngeal swabs for the analysis by RAT, reverse transcriptase real time polymerase chain reaction (RT-qPCR), and a cell culture based infection assay were collected from 67 patients that presented to the emergency department of the University Hospital of Graz (Austria). The first swab was used for on-site RAT testing in the emergency department using the Roche SARS-CoV-2 RAT. The second swab was sent to the central laboratory of the hospital for RT-qPCR with two independent methods (Cepheid Xpert® Xpress SARS-CoV-2 assay and Roche Cobas SARS-CoV-2 Test) and repeat RAT testing using the same commercial test. With the third swab a cell culture-based infection assay was performed.RESULTS:
The RATs performed from independent samples showed substantial agreement (Cohen's-kappa 0.73, p<0.001). All patients with a positive RAT had positive RT-qPCR with cycle threshold (ct) values <25. Fifteen out of 55 RAT-negative samples were RT-qPCR positive with ct values between 25 and 40. The inoculation of cell cultures with RT-qPCR negative swabs and RT-qPCR positive swabs with ct values >25 did not induce cytopathic effects that were related to SARS-CoV-2. The infection assays from four RAT-negative patients showed cytopathic effects that were induced by other pathogens.CONCLUSIONS:
The SARS-CoV-2 RAT from Roche Diagnostics is a valuable tool for managing symptomatic patients. RAT-negative patients may be regarded as non-contagious.Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
SARS-CoV-2
/
COVID-19
Type of study:
Diagnostic study
Limits:
Humans
Language:
English
Journal:
Clin Chem Lab Med
Journal subject:
Chemistry, Clinical
/
Laboratory Techniques and procedures
Year:
2022
Document Type:
Article
Affiliation country:
Cclm-2021-1276
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