Xpert MTB/RIF® como herramienta diagnóstica en una cohorte de niños menores de 15 años con sospecha clínica de tuberculosis pulmonar en un hospital de alta complejidad de Medellín

Abstract

Introduction: Microbiological confirmation of tuberculosis (TB) in children is difficult. Due to its paucibacillary course, the positivity of cultures is low and samples are not easy to obtain. In adults, Genexpert MTB/RIF is useful for diagnosing TB. It shows good test performance, offers fast results and is a simple technique for laboratory personnel. The World Health Organization (WHO) recommends its use for children, but clinical studies on this age group are scarce. Objective: This was a retrospective, descriptive cohort study. The purpose of this study was to describe our experience with Gene Xpert MTB/RIF in children younger than 15 years of age with clinical suspicion of pulmonary TB, who were admitted to a high complexity hospital. Methods: A total of 116 clinical charts with available results of Xpert MTB/RIF in respiratory samples taken between June 2012 and December 2013 were reviewed and of these, 33 were excluded. The 83 included patients were classified according to the WHO criteria into confirmed TB (n = 8; 10%), probable (n = 16; 19%) and no TB (n = 59; 71%). An analysis was performed using SPSS 20 and EpiDat 3.1. Results: The Xpert MTB/RIF was 50% sensitive and 96% specific, with a positive predictive value of 57.14% and an negative predictive value of 94.7% for children with confirmed TB. When evaluating Xpert MTB/RIF in all children who received TB treatment (confirmed plus probable TB disease) the sensitivity was 29% with 100% specificity. Among our cohort, the Xpert MTB/RIF detected one child with rifampicin resistance. Conclusions: Xpert MTB/RIF was useful for the diagnosis of TB. A positive result can lead to the early initiation of treatment in doubtful cases. It confirms the diagnosis and quickly reveals rifampicin resistance. A negative result, however, just as with cultures, does not exclude the diagnosis and should not prevent the initiation of treatment, if it is considered needed based on other criteria.