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Saliva is a reliable tool to detect SARS-CoV-2.

Author(s): Azzi L, Carcano G, Gianfagna F, Grossi P, Gasperina DD, Genoni A, Fasano M, Sessa F, Tettamanti L, Carinci F, Maurino V, Rossi A, Tagliabue A, Baj A

Publication: J Infect, 2020, Vol. , Page

PubMed ID: 32298676 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study investigated the use of salivary specimens for detection of SARS-CoV-2 in patients with SARS-CoV-2 positive nasopharyngeal specimens and investigated if SARS-CoV-2 was detected in a patient’s salivary specimen after the nasopharyngeal specimen became negative. The effects of period since onset of symptoms, LDH levels, us-CRP levels, patient age, patient sex, drug intake, and the presence of comorbidities on SARS-CoV-2 CT value was also investigated. Saliva was collected using the drooling method or intraorally using a pipette from 25 hospitalized patients (17 male and 8 female, age 39-85) with severe or very severe infections with SARS-CoV-2 diagnosed by nasopharyngeal swabs. A second saliva specimen was collected from eight patients 4 days later. Saliva was resuspended in PBS and RNA was extracted using the QIAmp Viral RNA Mini Kit and subjected to one-step RT-PCR using the Luna Universal qPCR Master Mix and primer for the 5’UTR of SARS-CoV-2. Specimens were classified as highly positive or low positive based on having a CT value below or above the median CT, respectively. Method of us-CRP and LDH determination was not specified.

   Summary of Findings:

   SARS-CoV-2 was detected in the initial saliva specimen from all 25 patients. The authors state there was no effect of period since onset of symptoms on salivary CT observed; however, regression analysis showed salivary RT-PCR values for SARS-CoV-2 were inversely correlated with LDH (β=-0.02, P= 0.04) and average LDH levels were significantly lower in male patients than female patients (304.3 versus 400.6, P=0.025). SARS-CoV-2 CT values were not significantly associated with us-CRP levels, patient age, patient sex, drug (anticoagulants, ACE-inhibitors, or statins) intake, or the presence of comorbidities such as dyslipidemia, hypertension, or obesity. The authors state there were no relevant differences in SARS-CoV-2 CT between the first and second salivary collection. Importantly, the authors report positive salivary specimens for 2 or more days after the nasopharyngeal specimen became negative.

   Biospecimens

   • Bodily Fluid - Saliva
   • Cell - Nasopharynx

   Preservative Types

   • None (Fresh)

   Diagnoses:

   • Pneumonia/Respiratory Infection

   Platform:

   Analyte	Technology Platform
   Protein	Clinical chemistry/auto analyzer
   RNA	Real-time qRT-PCR

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Preaquisition	Patient age	39-85 years old
   Preaquisition	Patient gender	Female Male
   Preaquisition	Prior patient medical condition	Existing dyslipidemia, hypertension, or obesity
   Preaquisition	Other drugs	Anticoagulants ACE-inhibitors Statins
   Biospecimen Acquisition	Biospecimen location	Nasopharynx Saliva
   Biospecimen Acquisition	Time of biospecimen collection	Current positive nasopharyngeal swab Day nasopharyngeal swab converted to negative Two days after nasopharyngeal swab converted to negative Unspecified duration since onset of symptoms
   Real-time qRT-PCR Specific	Targeted nucleic acid	SARS-CoV-2

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