Factors associated with false-negative results from the rapid molecular test for pulmonary tuberculosis in the state of São Paulo, Brazil

OBJECTIVE: To analyze the factors associated with the frequency of false negative results for the RMT-TB test for the diagnosis of pulmonary tuberculosis in the state of São Paulo. METHODS: Cross-sectional study using pulmonary tuberculosis cases from the state of São Paulo reported in the TB-WEB system between 2014 and 2023. RMT-TB results were compared with sputum smear microscopy, sputum culture, and sensitivity testing. Subsequently, variables with p<0.05 in the statistical tests were included in the logistic regression. RESULTS: There was a significant increase in the use of RMT-TB over the years, reaching 76% of cases in 2023. Analysis of the test accuracy revealed high agreement with sputum culture (82.6%) and the sensitivity test (98.4%), although it showed lower agreement with sputum smear microscopy (78.5%). The study identified factors associated with false-negative results on the RMT-TB, such as advanced age, female sex, HIV status, imprisoned, and a normal chest X-ray. Logistic regression confirmed that these factors increase the likelihood of false-negative results. CONCLUSION: The RMT-TB is an effective tool for diagnosing pulmonary tuberculosis, but the interpretation of results must consider each patient's specific risk factors, especially in high-risk populations. The study highlights the importance of combining the RMT-TB with other diagnostic methods and clinical evaluation to ensure accurate diagnosis and appropriate treatment.