Evaluation of the implementation of the Xpert (R) MTB/RIF assay in Fiji

Setting: All Xpert (R) MTB/RIF tests performed in the three TB (tuberculosis) treatment centres in Fiji from June 2012 to February 2013. Objectives: To determine 1) the number of Xpert tests performed in each centre, 2) the association between sputum quality and Xpert results, 3) the agreement of Xpert with acid-fast bacilli (AFB) smear microscopy and TB culture and 4) error rates. Design: Retrospective review of records. Results: A total of 415 Xpert tests were performed in the study period. Mycobacterium tuberculosis was detected in 69 (16.6%) samples. No rifampicin resistance was detected. M. tuberculosis was detected from 60 (18.7%) good-quality sputum samples. A total of 43 (10.4%) errors occurred during this period. M. tuberculosis was detected in 10 (2.9%) smear-negative specimens. There was a substantial and an almost perfect agreement between Xpert and AFB microscopy (kappa = 0.793) and culture results (kappa = 0.818), respectively. Conclusion: Although a good correlation between Xpert and the two tests were shown in the study, Xpert should not replace the routine first-line TB diagnostic tests used in Fiji for reasons related to logistics and sustainability. A further evaluation of the assay's performance is required over a longer time period to gauge its diagnostic value in detecting smear-negative, Xpert-positive cases in Fiji.