Assessing a chip based rapid RTPCR test for SARS CoV-2 detection (TrueNat assay): A diagnostic accuracy study.

COVID-19 testing is required before admission of a patient in the hospitals, invasive procedures, major and minor surgeries etc. Real Time Polymerase chain reaction is the gold standard test for the diagnosis, but requires well equipped biosafety laboratory along with trained manpower. In this study we have evaluated the diagnostic accuracy of novel TrueNat molecular assay for detecting SARS CoV-2. TrueNat is a chip-based real time PCR test and works on portable, light weight, battery powered equipment and can be used in remote areas with poor infrastructure. In this study 1807 patients samples were collected for both TrueNat and RTPCR COVID-19 testing during study period. Of these 174 (9.7%) and 174 (15%) were positive by RTPCR and TrueNat respectively and taking results of RTPCR as gold standard TrueNat test showed a sensitivity, specificity and diagnostic accuracy of 69.5, 90.9% and 89.2% respectively. It can be concluded that TrueNat is a simple, easy to use, good rapid molecular diagnostic test for diagnosis of COVID-19 especially in resource limited settings and will prove to be a game changer of molecular diagnostics in future.

Evaluation of seven commercial RT-PCR kits for COVID-19 testing in pooled clinical specimens.

There are more than 350 real-time polymerase chain reaction (RT-PCR) coronavirus disease-2019 (COVID-19) testing kits commercially available but these kits have not been evaluated for pooled sample testing. Thus, this study was planned to compare and evaluate seven commercially available kits for pooled samples testing. Diagnostic accuracy of (1) TRUPCR SARS-CoV-2 Kit (Black Bio), (2) TaqPath RT-PCR COVID-19 Kit (Thermo Fisher Scientific), (3) Allplex 2019-nCOV Assay (Seegene), (4) Patho detect COVID-19 PCR kit (My Lab), (5) LabGun COVID-19 RT-PCR Kit (Lab Genomics, Korea), (6) Fosun COVID-19 RT-PCR detection kit (Fosun Ltd.), (7) Real-time Fluorescent RT-PCR kit for SARS CoV-2 (BGI) was evaluated on precharacterised 40 positive and 10 negative COVID-19 sample pools. All seven kits detected all sample pools with low Ct values (<30); while testing weak positive pooled samples with high Ct value (>30); the TRUPCR Kit, TaqPath Kit, Allplex Assay, and BGI RT-PCR kit showed 100% sensitivity, specificity, and accuracy. However, the Fosun kit, LabGun Kit, and Patho detect kit could detect only 90%, 85%, and 75% of weakly positive samples, respectively. We conclude that all seven commercially available RT-PCR kits included in this study can be used for routine molecular diagnosis of COVID-19. However, regarding performing pooled sample testing, it might be advisable to use those kits that performed best regarding positive identification in samples' pool, that is TRUPCR SARS-CoV-2 Kit, TaqPath RT-PCR COVID-19 Kit, Allplex 2019-nCOV Assay, and BGI Real-time RT-PCR kit for detecting SARS CoV-2.

The Spectrum of Gastrointestinal Symptoms in Patients With Coronavirus Disease-19: Predictors, Relationship With Disease Severity, and Outcome.

INTRODUCTION: We prospectively studied the frequency, spectrum, and predictors of gastrointestinal (GI) symptoms among patients with coronavirus disease-19 (COVID-19) and the relationship between GI symptoms and the severity and outcome. METHODS: Consecutive patients with COVID-19, diagnosed in a university hospital referral laboratory in northern India, were evaluated for clinical manifestations including GI symptoms, their predictors, and the relationship between the presence of these symptoms, disease severity, and outcome on univariate and multivariate analyses. RESULTS: Of 16,317 subjects tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in their oropharyngeal and nasopharyngeal swabs during April-May 2020, 252 (1.5%) were positive. Of them, 208 (82.5%) were asymptomatic; of the 44 symptomatic patients, 18 (40.9%) had non-GI symptoms, 15 (34.1%) had a combination of GI and non-GI symptoms, and 11 (25.0%) had GI symptoms only. Thirty-three had mild-to-moderate disease, 8 severe, and 5 critical. Five patients (1.98%) died. On multivariate analysis, the factors associated with the presence of GI symptoms included the absence of contact history and presence of non-GI symptoms and comorbid illnesses. Patients with GI synptoms more often had severe, critical illness and fatal outcome than those without GI symptoms. DISCUSSION: Eighty-two percent of patients with COVID-19 were asymptomatic, and 10.3% had GI symptoms; severe and fatal disease occurred only in 5% and 2%, respectively. The presence of GI symptoms was associated with a severe illness and fatal outcome on multivariate analysis. Independent predictors of GI symptoms included the absence of contact history, presence of non-GI symptoms, and comorbid illnesses.(Equation is included in full-text article.).

A guide to laboratory diagnosis of Corona Virus Disease-19 for the gastroenterologists.

The outbreak of Corona Virus Disease-19 (COVID-19), caused by Severe Acute Respiratory Syndrome Corona Virus - 2 (SARS-CoV-2), a global pandemic, is having a significant impact on healthcare, especially the clinical microbiology laboratories all around the world. There are many reports which suggest that the disease can present with gastrointestinal symptoms such as nausea, vomiting, diarrhea, and loss of appetite, which the gastroenterologists may have to deal with. Hence, knowledge about the diagnosis of COVID-19 is important to gastroenterologists as well. The current review therefore covers the challenges faced while choosing appropriate sample collection, transport, and tests for SARS-CoV-2 infection. The right sample at the right time from the right anatomical site with the proper precautions is crucial in prompt and accurate diagnosis of COVID-19. The tests can be divided into direct, indirect, and complementary tests. In the direct test, real-time polymerase chain reaction (RT-PCR) assays are the molecular tests of choice for the diagnosis of COVID-19. Other direct tests include GeneXpert and TrueNAT. In indirect testing, antigen-antibody-based techniques are recommended for surveillance for the disease, which may help to formulate the control measures. Finally, the additional tests help in assessing the disease severity and evaluating the prognosis. All the above tests are important not only for diagnosis but also for management strategy and prognosis.