Padronização do ensaio RT-PCRq para detecção de SARS-CoV-2 em diferentes amostras clínicas: desafios e interferentes

Abstract

Objective: To describe the standardization of the RT-PCRq test in different clinical samples, the challenges, and interferences for SARS-CoV-2 detection. Methodology: Upper respiratory tract swab, serum, and urine samples were collected from 138 positive patients, along with swab samples from 67 negative patients. Patients over 18 years old, presenting with fever and/or respiratory symptoms within 7 days of onset, and confirmed COVID-19 diagnosis by the surveillance team were included. The samples underwent RNA extraction using the silica column method, followed by RT-PCRq. Results: The swab samples yielded 65 positive results (≤ 38 Ct), followed by urine (17) and serum (12). The study revealed a reasonable sensitivity percentage (47%) in upper respiratory tract swab samples when compared to the gold standard, with a significant difference (p<0.0001) between them. Conversely, for swab samples from negative patients, specificity was 100%, suggesting that the test provided accurate negative results in the absence of the disease. Conclusion: These findings underscore the importance of quality control practices and standardization to prevent false results, in addition to integrating the technique with point-of-care tests and clinical resources for accurate and effective COVID-19 diagnosis.