PA-21 Accuracy of GeneXpert Ultra for diagnosis of childhood tuberculosis within national public health systems in West Africa – a multicentre pragmatic study

Abstract

<h3>Background</h3> We conducted a pragmatic evaluation of GeneXpert Ultra (‘Ultra’) for diagnosis of childhood tuberculosis (TB) within national public health systems in West Africa. <h3>Methods</h3> In this cross-sectional study, children (&lt;15 years) with presumed pulmonary TB were consecutively recruited and evaluated at three tertiary hospitals in Benin, Ghana, and Mali. Bivariate random-effects models were used to determine the pooled sensitivity and specificity of Ultra against a microbiological reference standard ([MRS]; liquid culture) and a composite reference standard ([CRS]; culture-confirmed TB and unconfirmed TB). <h3>Results</h3> Overall, we enrolled 193 children with a median (IQR) age of 3.2 (1.1 - 8.9) years, 88 (46%) were female, and HIV prevalence was 36/142 (25%). 32 (17%) children had confirmed TB, 39 (20%) had unconfirmed TB, and 122 (63%) had unlikely TB. Using MRS, the pooled sensitivity and specificity of Ultra were 55% (95% CI: 28 - 79%) and 95% (95% CI: 88 - 98%), respectively. Ultra demonstrated sensitivity and specificity of 50% (95% CI: 16 - 84%) and 95% (95% CI: 85 - 99%), respectively, using sputum, as against sensitivity of 46% (95% CI 17 - 77%) and specificity of 93% (95% CI: 87 - 97%) for gastric aspirate. Against the CRS, the pooled sensitivity and specificity of Ultra decreased to 17% (95% CI: 4 - 53%) and 93% (95% CI: 87 - 96%), respectively. Using sputum, sensitivity and specificity of Ultra were 24% (95% CI: 7 - 50%) and 94% (95% CI: 82 - 99%), respectively, compared with sensitivity of 14% (95% CI: 5 - 30%) and specificity of 91% (95% CI: 82 - 96%) using gastric aspirate. <h3>Conclusion</h3> The suboptimal sensitivity of Ultra in children with TB investigated routinely within national public health systems in West Africa constitutes a major challenge. Funding: EDCTP-West African Networks of Excellence for TB, AIDS &amp; Malaria.