tetano
Editor, Senior Moderator
Clin Infect Dis. 2020 Mar 28. pii: ciaa345. doi: 10.1093/cid/ciaa345. [Epub ahead of print]
Quantitative Detection and Viral Load Analysis of SARS-CoV-2 in Infected Patients.
Yu F[SUP]1,[/SUP][SUP]2[/SUP], Yan L[SUP]1,[/SUP][SUP]2[/SUP], Wang N[SUP]3,[/SUP][SUP]4[/SUP], Yang S[SUP]1,[/SUP][SUP]2[/SUP], Wang L[SUP]1,[/SUP][SUP]2[/SUP], Tang Y[SUP]1,[/SUP][SUP]2[/SUP], Gao G[SUP]1,[/SUP][SUP]2[/SUP], Wang S[SUP]1,[/SUP][SUP]2[/SUP], Ma C[SUP]1,[/SUP][SUP]2[/SUP], Xie R[SUP]1,[/SUP][SUP]2[/SUP], Wang F[SUP]5[/SUP], Tan C[SUP]5[/SUP], Zhu L[SUP]3[/SUP], Guo Y[SUP]5[/SUP], Zhang F[SUP]1,[/SUP][SUP]2[/SUP].
Author information
Abstract
BACKGROUND:
Coronavirus disease 2019 (COVID-19) has become a public health emergency. The widely used reverse transcription PCR (RT-PCR) method has limitations for clinical diagnosis and treatment.
METHODS:
A total of 323 samples from 76 COVID-19 confirmed patients were analyzed by droplet digital PCR (ddPCR) and RT-PCR based two target genes (ORF1ab and N). Nasal swabs, throat swabs, sputum, blood, and urine were collected. Clinical and imaging data were obtained for clinical staging.
RESULTS:
In 95 samples tested positive by both methods, the cycle threshold (Ct) of RT-PCR was highly correlated with the copy numbed of ddPCR (ORF1ab gene, R2 = 0.83; N gene, R2 = 0.87). 4 (4/161) negative and 41 (41/67) single-gene positive samples tested by RT-PCR were positive according to ddPCR with viral load ranging from 11.1 to 123.2 copies/test. Then the viral load of respiratory samples was compared and the average viral load in sputum (17429 ? 6920 copies/test) was found to be significantly higher than in throat swabs (2552 ? 1965 copies/test, p < 0.001) and nasal swabs (651 ? 501 copies/test, p < 0.001). Furthermore, the viral load in the early and progressive stages were significantly higher than that in the recovery stage (46800 ? 17272 vs 1252 ? 1027, p < 0.001) analyzed by sputum samples.
CONCLUSIONS:
Quantitative monitoring of viral load in lower respiratory tract samples helps to evaluate disease progression, especially in cases of low viral load.
? The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
KEYWORDS:
COVID-19; RT-PCR; SARS-CoV-2; Viral load; ddPCR
PMID:32221523DOI:10.1093/cid/ciaa345
Quantitative Detection and Viral Load Analysis of SARS-CoV-2 in Infected Patients.
Yu F[SUP]1,[/SUP][SUP]2[/SUP], Yan L[SUP]1,[/SUP][SUP]2[/SUP], Wang N[SUP]3,[/SUP][SUP]4[/SUP], Yang S[SUP]1,[/SUP][SUP]2[/SUP], Wang L[SUP]1,[/SUP][SUP]2[/SUP], Tang Y[SUP]1,[/SUP][SUP]2[/SUP], Gao G[SUP]1,[/SUP][SUP]2[/SUP], Wang S[SUP]1,[/SUP][SUP]2[/SUP], Ma C[SUP]1,[/SUP][SUP]2[/SUP], Xie R[SUP]1,[/SUP][SUP]2[/SUP], Wang F[SUP]5[/SUP], Tan C[SUP]5[/SUP], Zhu L[SUP]3[/SUP], Guo Y[SUP]5[/SUP], Zhang F[SUP]1,[/SUP][SUP]2[/SUP].
Author information
Abstract
BACKGROUND:
Coronavirus disease 2019 (COVID-19) has become a public health emergency. The widely used reverse transcription PCR (RT-PCR) method has limitations for clinical diagnosis and treatment.
METHODS:
A total of 323 samples from 76 COVID-19 confirmed patients were analyzed by droplet digital PCR (ddPCR) and RT-PCR based two target genes (ORF1ab and N). Nasal swabs, throat swabs, sputum, blood, and urine were collected. Clinical and imaging data were obtained for clinical staging.
RESULTS:
In 95 samples tested positive by both methods, the cycle threshold (Ct) of RT-PCR was highly correlated with the copy numbed of ddPCR (ORF1ab gene, R2 = 0.83; N gene, R2 = 0.87). 4 (4/161) negative and 41 (41/67) single-gene positive samples tested by RT-PCR were positive according to ddPCR with viral load ranging from 11.1 to 123.2 copies/test. Then the viral load of respiratory samples was compared and the average viral load in sputum (17429 ? 6920 copies/test) was found to be significantly higher than in throat swabs (2552 ? 1965 copies/test, p < 0.001) and nasal swabs (651 ? 501 copies/test, p < 0.001). Furthermore, the viral load in the early and progressive stages were significantly higher than that in the recovery stage (46800 ? 17272 vs 1252 ? 1027, p < 0.001) analyzed by sputum samples.
CONCLUSIONS:
Quantitative monitoring of viral load in lower respiratory tract samples helps to evaluate disease progression, especially in cases of low viral load.
? The Author(s) 2020. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.
KEYWORDS:
COVID-19; RT-PCR; SARS-CoV-2; Viral load; ddPCR
PMID:32221523DOI:10.1093/cid/ciaa345