Usefulness of TrueNat: A Chip-based Real-time PCR Test for COVID-19

Abstract

Introduction: For the containment of growing Coronavirus Disease (COVID-19) pandemic, rapid diagnostic facilities are need of today. Indigenously developed TrueNat assay is a point-of-care assay developed for early diagnosis of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2). It is a portable, fully automated, chip-based, real-time quantitative polymerase chain reaction system with a turnaround time of 1.5-2 hours. Aim: To assess the practical utility and diagnostic accuracy of TrueNat testing for COVID-19 in a pandemic situation. Materials and Methods: A cohort selection cross-sectional study was conducted from July to September 2020 at Department of Biochemistry, Vardhaman Institute of Medical Sciences, Pawapuri, Bihar, India, after obtaining Institutional Ethics Committee (IEC) approval. A total of 296 cases with symptoms of COVID-19 were selected for the study. Assuming real-time Reverse TranscriptionPolymerase Chain Reaction (rRT-PCR) to be the gold standard, we collected oropharyngeal swabs from symptomatic COVID-19 suspected cases and tested by both TrueNat and standard RT-PCR. Agreement between both the assays were assessed by overall, Positive Percent Agreement (PPA) and Negative Percent Agreement (NPA) and Cohen’s kappa coefficient using Epitools (Ausvet 2020). Results: Out of 296 oropharyngeal swabs taken from suspected COVID-19 patients, 19 were read as “invalid” and discarded; hence only 277 samples were tested by TrueNat and RT-PCR both. Assuming RT-PCR as standard, TrueNat assay demonstrated an overall percent agreement of 99.64%, PPA of 95.65%, NPA 99.81%. The kappa coefficient was 0.9546. Conclusion: TrueNat assay offers a rapid, accurate and affordable technique for COVID-19. It may be deployed for mass screening and confirmation of COVID-19 cases in hospitals and remote areas.

Keywords

• coronavirus disease-19
• molecular diagnostic test
• polymerase chain reaction
• point-of-care assay
• rapid test