Xpert MTB/RIF assay in rapid diagnosis of tuberculous lymphadenitis

Abstract

Objective To assess the application of Xpert MTB/RIF assay in rapid diagnosis of tuberculous lymphadenitis. Methods Lymph node samples were collected from 102 clinically diagnosed patients with lymph node tuberculosis and 65 patients with other lymph node diseases from Zhejiang Provincial Hospital of Traditional Chinese and Western Medicine during January 2014 and February 2015. Xpert MTB/RIF, pathological examination and mycobacterium tuberculosis culture were conducted in all specimens of two groups. Taking clinical comprehensive diagnosis as the gold standard, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value and diagnosis efficacy of three detection methods were assessed. The sensitivity of Xpert MTB/RIF in determining rifampicin resistance was analyzed using drug susceptibility testing as gold standard. Results The mean detection time of Xpert MTB/RIF was (2.2±0.2) h. Among 102 patients, Xpert MTB/RIF achieved higher sensitivity (96.1%, 98/102) than pathological examination (76.5%, 78/102) and mycobacterium tuberculosis culture (33.3%, 34/102)(χ2=16.558 and 87.919, both P<0.01). Among 65 patients with other lymph node diseases, the specificity of all three detection methods was 100%. The receiver-operating-characteristic curve analysis demonstrated that diagnostic performance of Xpert MTB/RIF was better than that of other two methods. In 8 patients resistant to rifampicin confirmed by drug susceptibility testing, Xpert MTB/RIF detected 6 resistant-resistant patients. Conclusion Xpert MTB/RIF shows higher sensitivity and specificity in diagnosis of lymph node tuberculosis with the advantages of easy and rapid performance. Key words: Tuberculosis, lymph node; Xpert MTB/RIF; Nucleic acid amplification techniques; Early diagnosis