Detection and Isolation of SARS-CoV-2 in Serum, Urine, and Stool Specimens of COVID-19
Detection and Isolation of SARS-CoV-2 in Serum, Urine, and Stool Specimens of COVID-19. Jefferson T, Heneghan C.
Published on September 1, 2020
Transmission Dynamics of COVID-19
||Kim JM, Kim HM, Lee EJ, et al. Detection and Isolation of SARS-CoV-2 in Serum, Urine, and Stool Specimens of COVID-19 Patients from the Republic of Korea Osong Public Health Res Perspect. 2020;11(3):112-117.
||Korea Centers for Disease Control and Prevention
||Viral Load, Respiratory, stool, blood, urine
No viral growth was detected in respiratory, urine, stool and blood samples despite a positive RT-PCR very soon after admission.
There were 323 serum samples, 247 urine samples, and 129 stool samples collected and tested. SARS-CoV-2 RNA detection rates were 2.8% (9/323), 0.8% (2/247), and 10.1% (13/129), respectively.
In 15 patients (20.0%), SARS-CoV-2 was detected at least once in at least 1 of the 3 specimens, apart from the respiratory specimens. In four of these patients, the virus was detectable in the serum and stool samples for a longer period than in the respiratory samples.
The virus was detected in serum samples of six patients, urine samples of two patients, and stool samples of eight patients. Viral RNA was detected in the serum of five patients at 3-6 days after onset.
The virus detection rate in the serum, urine, and stool samples were 2.8% (9/323), 0.8% (2/247), and 10.1% (13/129), and the mean viral load was 1,210 ± 1,861, 79 ± 30, and 3,176 ± 7,208 copy/μL, respectively. However, the SARS-CoV-2 was not isolated by the culture method from the samples that tested positive for the SARS-CoV-2 gene.
What did they do?
The study investigated whether SARS-CoV-2 can be detected in body fluids (serum, urine, stool and respiratory specimens and to isolate the virus from positive samples to determine viral infectivity.
Nasopharyngeal swabs, oropharyngeal swabs or sputum (at least twice), serum (71), urine (54), and stool specimens (38) were sampled from 74 COVID-19 hospital patients between January 19th and March 30th, 2020. 44 were male and 30 were female aged 9-80 years (median 43 years). The maximum period of sample collection was 17 days from the date of disease confirmation.
RT-PCR was performed on the target genes were E and RdRp. Cell culture was performed in a Level III facility by inoculum into CaCo-2 cell line after stabilisation at 4C and harvested after 5 days and the supernatant after centrifugation was re-inoculated for another 5 days and assessed with RT-PCR.
The study is chaotically and confusingly reported: it is not clear whether the source patients were symptomatic or not, the specimen tallyflow and the lexicon is different from methods to results. Virus “detected” “found” and “cultured” are terms which are not explained in the text and appear to be used in an interchangeable way.
|Clearly defined setting
||Demographic characteristics described
||Follow-up length was sufficient
||Transmission outcomes assessed
||Main biases are taken into consideration
What else should I consider?
The results of this study should not be taken into consideration.
About the authors
Carl is Professor of EBM & Director of CEBM at the University of Oxford. He is also a GP and tweets @carlheneghan. He has an active interest in discovering the truth behind health research findings
Tom Jefferson, epidemiologist.