The role of saliva PCR assay in the diagnosis of COVID-19

  • Alireza Abdollahi Department of pathology, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
  • Samaneh Salarvand Department of pathology, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
  • Reza Ghalehtaki Department of Radiation Oncology, Cancer Institute, Imam Khomeini Hospital Complex, Tehran, Iran
  • Bita Jafarzadeh Department of pathology, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
  • Mohammad Taghi Beigmohammadi Department of infectious diseases, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
  • Fereshteh Ghiasvand Department of infectious diseases, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
  • Abbas Shakoori Medical Genetic Ward, Imam Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
  • Hoda Khoshnevis Medical Genetic Ward, Imam Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
  • Mohammad Arabzadeh Medical Genetic Ward, Imam Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran
  • Saeed Nateghi Department of Cardiology, Tehran University of Medical Sciences, Tehran, Iran
  • Vahid Mehrtash Department of pathology, Imam Hospital Complex, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Keywords: COVID-19, saliva; PCR, nasopharynx, oropharynx

Abstract

Introduction: The introduction of a self-collection sampling method with less discomfort would be of great benefit in reducing the risk of medical provider's contamination and patient's acceptance. The aim of the present study was to investigate saliva samples' diagnostic performance for the COVID-19 RT-PCR test compared to pharyngeal swabs.

Methodology: From individuals referred to a medical center with presentations compatible with COVID-19 who were eligible for molecular diagnostic tests, 80 cases were selected. Nasopharyngeal and oropharyngeal swabs (placed into the same transport tube) along with self-collected saliva sample were taken from each participant for COVID-19 RT-PCR assay. The results of pharyngeal swabs and saliva sample were compared.

Results: Sixty-two (78%) infected cases were detected, of whom 31 (39%) cases tested positive for both pharyngeal swab and saliva samples. 24 (30%) and 7 (9%) cases tested positive only for pharyngeal or saliva samples, respectively. The overall percentage of agreement between pharyngeal swab and saliva sample was 61%, with a kappa value of 0.24 (p-value = 0.019, 95% CI: 0.04-0.44), showing a fair level of agreement. The diagnostic sensitivity of pharyngeal swabs was 88.71% (95% CI: 78.11-95.34), and the diagnostic sensitivity of saliva samples was 61.29% (95% CI: 48.07-73.40). Compared to pharyngeal swabs (oropharyngeal and nasopharyngeal swabs in the same collection tube), an important observation was that seven more positive cases were detected among saliva samples.

Conclusions: The findings of the present study indicated that self-collected saliva samples cannot replace pharyngeal swabs. Still, saliva samples significantly increased the case detection rate and can be used along with pharyngeal swabs.

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Published
2022-01-31
How to Cite
1.
AbdollahiA, SalarvandS, Ghalehtaki R, Jafarzadeh B, BeigmohammadiMT, GhiasvandF, Shakoori A, Khoshnevis H, Arabzadeh M, Nateghi S, Mehrtash V (2022) The role of saliva PCR assay in the diagnosis of COVID-19. J Infect Dev Ctries 16:5-9. doi: 10.3855/jidc.15239
Section
Coronavirus Pandemic