Impacto da qualidade do escarro, na positividade do XpertMTB/RIF, na busca ativa de casos de tuberculose pulmonar

Abstract

Introduction: Studies evaluating the relationship between sputum quality and GeneXpertMTB/RIF (Xpert) positivity in the context of active case finding for tuberculosis (TB) are scarce. The aim of this study was to determine the association between sputum quality and Xpert positivity and whether the association differed according to demographic and clinical characteristics in the context of TB mass screening. Design/Methods: A cross-sectional study was conducted involving people deprived of liberty (PDL) who served their sentences in a closed regime in three places in the state of Mato Grosso do Sul, Brazil: Penitenciária Estadual de Dourados (PED), Estabelecimento Penal Jair Ferreira de Carvalho (EPJFC) e Instituto Penal de Campo Grande (IPCG). Data were collected between November 2017 and August 2021. Was administered a standardized questionnaire was applied to collect sociodemographic and clinical information, as well as risk factors for TB, including illicit drugs, smoking and history of the disease. In addition, a posteroanterior radiography was performed and a sputum sample was collected to perform the Xpert rapid molecular test. Sputum quality was defined as “mucoid/mucopurulent”, “bloody” and “salivary”, using two experienced laboratory workers. Data were analyzed using binomial logarithmic regression, using the R program to estimate the relationship between sputum quality and Xpert positivity, evaluating interactions with participant characteristics. Results: Among 4,368 (39.5%) had sputum quality assessed and Xpert performed, 3,379 (77.4%) had mucoid/mucopurulent sputum, 957 (21.9%) had salivary samples and 32 (0.7%) had bloody sputum. Xpert positivity was higher among those with mucoid/mucopurulent sputum 406 (12.0%) compared to those with saliva samples 35 (3.7%). An association was observed between the assessment of sputum quality, risk factors for TB such as smoking, abnormal symptom X-rays in CAD4TB, symptom screening and previous TB and Xpert positivity. Conclusions: In our study, the appearance of mucoid/mucopurulent sputum and some risk factors for TB, were related to greater Xpert positivity, highlighting the importance of careful assessment of sputum quality and attention to risk factors when performing TB diagnostic tests.