Role of Xpert MTB/RIF in differentiating tuberculosis from sarcoidosis in patients with mediastinal lymphadenopathy undergoing EBUS-TBNA: a study of 147 patients

Main Article Content

Sahajal Dhooria
Nalini Gupta
Amanjit Bal
Inderpaul Singh Sehgal
Ashutosh Nath Aggarwal
Sunil Sethi
Digambar Behera
Ritesh Agarwal

Keywords

sarcoidosis, tuberculosis, endobronchial ultrasound, endoscopic ultrasound, pcr, GeneXpert

Abstract

Background: In patients with intrathoracic lymphadenopathy, differentiating tuberculosis from sarcoidosis is often difficult. We hypothesized that Xpert MTB/RIF assay, a semi-automated hemi-nested PCR would help in this regard. Objective: To evaluate the performance of Xpert MTB/RIF in the differential diagnosis of tuberculosis and sarcoidosis. Methods: This was a retrospective analysis of patients with intrathoracic lymphadenopathy who underwent endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA), and were diagnosed as either tuberculosis or sarcoidosis. The results of Xpert MTB/RIF assay, tuberculin skin test and endosonographic characteristics (heterogeneous echotexture and coagulation necrosis sign) of the lymph nodes were compared between the two groups. Results: During the study period, 465 EBUS procedures were performed and a diagnosis of sarcoidosis (n=94) or tuberculosis (n=53) was made in 147 patients. Xpert MTB/RIF was positive in 26 (49.1%) and two (2.1%) patients with tuberculosis and sarcoidosis, respectively. The sensitivity, specificity, positive and negative predictive values of Xpert MTB/RIF in the diagnosis of tuberculosis were 49.1 %, 97.9%, 92.9% and 77.3%, respectively. The presence of any of the four features namely positive Xpert MTB/RIF, positive tuberculin skin test, heterogeneous echotexture of the lymph nodes, or the presence of endosonographic coagulation necrosis sign yielded a sensitivity and negative predictive value of 83.0% and 88.0%, respectively in the diagnosis of tuberculosis versus sarcoidosis. Conclusions: Xpert MTB/RIF has good specificity and positive predictive value in the diagnosis of tuberculosis, and is a useful investigation in separating tuberculosis from sarcoidosis. 

 

Downloads

Download data is not yet available.
Abstract 264 | PDF Downloads 166