Investigação do SARS-CoV-2 para rastreamento da COVID-19 por meio da RT-PCR em Pool Testing

Abstract

From the discovery of the coronavirus in 1964 to the present day, laboratory diagnosis of the virus is an important tool for detecting new cases, monitoring the historical series and planning actions according to the incidence of the disease. The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is the infectious agent responsible for the 2019 coronavirus disease (COVID-19) pandemic, with asymptomatic infected cases, mild, moderate, severe and deaths. The diagnosis considered the gold standard for detection of SARS-CoV-2 is the polymerase chain reaction coupled to real-time reverse transcription (RT-qPCR), which occurs through the extraction of ribonucleic acid (RNA) and has a high monetary cost. However, the diagnostic method developed in the Second World War, known as pool testing, aims to group more than two samples and use the reagents as if they were for a sample. individually to know which sample(s) was/were detectable, and if the pool is undetectable/negative, all samples are undetectable, thus causing an optimization of material and financial resources. The general objective of this research was to evaluate the pool testing method in RT-PCR for the investigation of SARS-CoV-2 in patients with flu syndrome and in asymptomatic patients. In the method, samples were collected at UPA Centro Sul from suspected cases of COVID-19 and from medical students during the internship without signs and symptoms. The samples were analyzed using RT-qPCR using pool testing between the period from September 2020 to April 2021. Among the results, from the 1,358 participants examined from the UPA through 504 pools with sample grouping ranging from 3 to 16. Among pools 33.7% were undetectable, and overall 32.62% of individual samples were detectable for SARS-CoV-2. Among those surveyed, 56.7% were female, the age group with the highest search for the test was between 18 and 39 years old, but who presented the highest percentage of positivity were people over 70 years old, with 48.1%. Among medical students, 15 pools were performed with 10 samples and 1 pool with 4 samples (total = 154 participants), all pools with undetectable results, 54.7% were male. In this way, pool testing proves to be a feasible and viable method for the diagnosis of SARS-CoV-2, especially in low prevalence, such as in asymptomatic, mild and moderate cases, reducing costs and optimizing resources.