Diagnostic Accuracy of Xpert MTB/RIF Assay in Diagnosis of Pulmonary Tuberculosis

Objectives/Background: The objectives of this study are to assess diagnostic of Xpert MTB/RIF assay for pulmonary tuberculosis (PTB) diagnosis and to compare it with microscopy (Ziehl-Neelsen staining) in the detection of pulmonary TB in Anambra state, Nigeria. Methods: A total of 1500 individuals with presumptive PTB participated. Participant’s age ranged from 15 years and above. Two sputum specimens were submitted on-the spot (S-S) within an hour interval. Sputum specimens were processed directly from Xpert MTB/RIF test according to manufacturer’s protocol whereas sputum smears were stained using Ziehl-Neelsen technique. Results: Xpert MTB/RIF test detected Mycobacterium tuberculosis (MTB) in 389 (25.9%) out of 1500 sputum specimens while microscopy detected only 237 (15.8%). Xpert MTB/RIF thus detected all the 237 smear positive cases of microscopy in addition to 152 (12.0%) positive cases among 1263 smear negative cases. Among 389 specimens with MTB detected by Xpert, Rifampicin resistance was seen in 12 (3.1%) cases. Most of the PTB patients were young men whose occupation was trading. Conclusion: Xpert MTB/Rif assay is an accurate method for rapid diagnosis of PTB. It outperformed microscopy and detected MTB in smear negative cases. It could therefore be used as an initial diagnostic test for PTB detection and rifampicin resistance in Anambra and Nigeria in general.

Author(s):

Nwachukwu O Ndubuisi1, Onyeagba R Azuonye1, Nwaugo O Victor1, Ononiwu A Happiness1 and Okafor C Daniel2

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