A retrospective audit assessing the efficacy of the GeneXpert test in diagnosing TB in a paediatric population

<b>Introduction:</b> GeneXpert is a molecular TB test which detects the presence of TB DNA in samples such as sputum and can publish results in less than 2 hours. <b>Objective:</b> In this study, a retrospective audit of the paediatric TB cases from a tertiary paediatric unit was carried out, looking at the sensitivity of GeneXpert in diagnosing TB in this population using sputum and lymph node samples. <b>Methods:</b> This study considered 77 patients with active paediatric TB who were diagnosed between January 2011 and March 2021. Data from electronic records was entered onto a pro forma, with the results analysed and the sensitivity of GeneXpert calculated for pulmonary and extra-pulmonary TB. <b>Results:</b> GeneXpert exhibited an overall sensitivity of 55% (11/20) when all sample types are amalgamated. Sputum samples exhibited a sensitivity of 54% (7/13) for pulmonary TB and 100% (1/1) for extra-pulmonary TB. The lymph nodes samples gave a 100% sensitivity for pulmonary (2/2) as well as extra-pulmonary (3/3) TB. It was also noted that only 26% (20/77) of TB patients in this audit were tested using GeneXpert. <b>Conclusion:</b> GeneXpert has a greater sensitivity for extra-pulmonary samples, with lymph node being the most reliable sample type. The results for GeneXpert in this audit are lower than have been recorded in past studies. However, the sensitivity of this test compares favourably to that of sputum cultures, stool cultures and gastric aspirate samples from this audit, indicating its potential effectiveness at diagnosing TB compared to the current standard methods.