Ultrasensitive Measurement of Both SARS-CoV-2 RNA and Antibodies from Saliva.

Dmitry Ter-Ovanesyan,Alexandra Rosenthal,Xu Yu,George M Church,Roey Lazarovits,Jonathan Z Li,Tal Gilboa,David R Walt

doi:10.1021/acs.analchem.1c00515

Dmitry Ter-Ovanesyan, Alexandra Rosenthal + Show 6 more

Open Access

https://doi.org/10.1021/acs.analchem.1c00515

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Abstract

Tests for COVID-19 generally measure SARS-CoV-2 viral RNA from nasal swabs or antibodies against the virus from blood. It has been shown, however, that both viral particles and antibodies against those particles are present in saliva, which is more accessible than both swabs and blood. We present methods for highly sensitive measurements of both viral RNA and antibodies from the same saliva sample. We developed an efficient saliva RNA extraction method and combined it with an ultrasensitive antibody test based on single molecule array (Simoa) technology. We apply our test to the saliva of patients who presented to the hospital with COVID-19 symptoms, some of whom tested positive with a conventional RT-qPCR nasopharyngeal swab test. We demonstrate that combining viral RNA detection by RT-qPCR with antibody detection by Simoa identifies more patients as infected than either method alone. Our results demonstrate the utility of combining viral RNA and antibody testing from saliva, a single easily accessible biofluid.

Highlights

The two main tests for SARS-CoV-2 infection are molecular tests to detect the presence of the virus (RNA or antigen) and serological tests to detect the presence of antibodies against the virus.[1−7] Both tests have advantages and disadvantages
We demonstrate that combining viral RNA detection by RT-qPCR with antibody detection by single molecule array (Simoa) identifies more patients as infected than either method alone
RT-qPCR tests for SARS-CoV-2 mostly analyze RNA from nasal swabs, while serology tests are generally performed using blood.[1,23,28−30] studies have shown that both SARSCoV-2 viral RNA15,31−34 and antibodies[20,31,35] against the virus are present in saliva

Summary

■ INTRODUCTION

The two main tests for SARS-CoV-2 infection are molecular tests to detect the presence of the virus (RNA or antigen) and serological tests to detect the presence of antibodies against the virus.[1−7] Both tests have advantages and disadvantages. RT-qPCR tests for SARS-CoV-2 mostly analyze RNA from nasal swabs, while serology tests are generally performed using blood.[1,23,28−30] studies have shown that both SARSCoV-2 viral RNA15,31−34 and antibodies[20,31,35] against the virus are present in saliva. We adapted a single molecule array[40] (Simoa)-based ultrasensitive test we previously developed for detecting SARS-CoV-2 antibodies in blood for use in saliva.[8,41] Combining our RNA extraction protocol for RT-qPCR with this ultrasensitive antibody test, we are able to better classify COVID-19 patients as being actively or previously infected with SARS-CoV-2, demonstrating the utility of this approach for accurate diagnosis of COVID-19

■ RESULTS AND DISCUSSION

■ ACKNOWLEDGMENTS

■ REFERENCES