tetano
Editor, Senior Moderator
J Infect Dis
. 2020 Aug 1;jiaa487.
doi: 10.1093/infdis/jiaa487. Online ahead of print.
Prospective study comparing deep-throat saliva with other respiratory tract specimens in the diagnosis of novel coronavirus disease (COVID-19)
Christopher K C Lai[SUP] 1 [/SUP], Zigui Chen[SUP] 1 [/SUP], Grace Lui[SUP] 2 3 [/SUP], Lowell Ling[SUP] 4 [/SUP], Timothy Li[SUP] 2 [/SUP], Martin C S Wong[SUP] 5 [/SUP], Rita W Y Ng[SUP] 1 [/SUP], Eugene Y K Tso[SUP] 6 [/SUP], Tracy Ho[SUP] 2 [/SUP], Kitty S C Fung[SUP] 6 [/SUP], Siu T Ng[SUP] 2 [/SUP], Barry K C Wong[SUP] 6 [/SUP], Siaw S Boon[SUP] 1 [/SUP], David S C Hui[SUP] 2 3 [/SUP], Paul K S Chan[SUP] 1 3 [/SUP]
Affiliations
Abstract
Background: Self-collected specimens has been advocated to avoid infectious exposure to healthcare workers. Self-induced sputum in those with a productive cough, and saliva in those without a productive cough have been proposed, but sensitivity remains uncertain.
Methods: We performed a prospective study in two regional hospitals in Hong Kong.
Results: We prospectively examined 563 serial samples collected during the virus shedding periods of 50 patients: 150 deep-throat saliva (DTS), 309 pooled-nasopharyngeal (NP) and throat swabs, and 104 sputum. DTS had the lowest overall RT-PCR positive rate (68.7% vs. 89.4% [sputum] and 80.9% [pooled NP and throat swabs]), and the lowest viral RNA concentration (mean log copy/mL 3.54 vs. 5.03 [sputum] and 4.63 [pooled NP and throat swabs]). Analyses with respect to time from symptom onset and severity also revealed similar results. Virus yield of DTS correlated with that of sputum (Pearson correlation index [95% CI]: 0.76 [0.62 - 0.86]). We estimated the overall false-negative rate of DTS could be 31.3%, and increased 2.7 times among patients without sputum.
Conclusion: DTS produced the lowest viral RNA concentration and RT-PCR positive rate compared to conventional respiratory specimens in all phases of illness. Self-collect sputum should be the choice for patients with sputum.
Keywords: COVID-19; SARS-CoV-2; coronavirus; diagnosis; novel infectious disease; saliva.
. 2020 Aug 1;jiaa487.
doi: 10.1093/infdis/jiaa487. Online ahead of print.
Prospective study comparing deep-throat saliva with other respiratory tract specimens in the diagnosis of novel coronavirus disease (COVID-19)
Christopher K C Lai[SUP] 1 [/SUP], Zigui Chen[SUP] 1 [/SUP], Grace Lui[SUP] 2 3 [/SUP], Lowell Ling[SUP] 4 [/SUP], Timothy Li[SUP] 2 [/SUP], Martin C S Wong[SUP] 5 [/SUP], Rita W Y Ng[SUP] 1 [/SUP], Eugene Y K Tso[SUP] 6 [/SUP], Tracy Ho[SUP] 2 [/SUP], Kitty S C Fung[SUP] 6 [/SUP], Siu T Ng[SUP] 2 [/SUP], Barry K C Wong[SUP] 6 [/SUP], Siaw S Boon[SUP] 1 [/SUP], David S C Hui[SUP] 2 3 [/SUP], Paul K S Chan[SUP] 1 3 [/SUP]
Affiliations
- PMID: 32738137
- DOI: 10.1093/infdis/jiaa487
Abstract
Background: Self-collected specimens has been advocated to avoid infectious exposure to healthcare workers. Self-induced sputum in those with a productive cough, and saliva in those without a productive cough have been proposed, but sensitivity remains uncertain.
Methods: We performed a prospective study in two regional hospitals in Hong Kong.
Results: We prospectively examined 563 serial samples collected during the virus shedding periods of 50 patients: 150 deep-throat saliva (DTS), 309 pooled-nasopharyngeal (NP) and throat swabs, and 104 sputum. DTS had the lowest overall RT-PCR positive rate (68.7% vs. 89.4% [sputum] and 80.9% [pooled NP and throat swabs]), and the lowest viral RNA concentration (mean log copy/mL 3.54 vs. 5.03 [sputum] and 4.63 [pooled NP and throat swabs]). Analyses with respect to time from symptom onset and severity also revealed similar results. Virus yield of DTS correlated with that of sputum (Pearson correlation index [95% CI]: 0.76 [0.62 - 0.86]). We estimated the overall false-negative rate of DTS could be 31.3%, and increased 2.7 times among patients without sputum.
Conclusion: DTS produced the lowest viral RNA concentration and RT-PCR positive rate compared to conventional respiratory specimens in all phases of illness. Self-collect sputum should be the choice for patients with sputum.
Keywords: COVID-19; SARS-CoV-2; coronavirus; diagnosis; novel infectious disease; saliva.