Evaluation of three immunological tests for the diagnosis of pulmonary tuberculosis in a rural endemic area of Bangladesh

Mohammad Tariqul Islam; Fazle Rabbi; Shameema Ferdous; Ummey Shahnaz Parvin; Akram Hossain; Mohammad Sorowar Hossain

doi:10.1016/j.ijmyco.2014.03.003

Evaluation of three immunological tests for the diagnosis of pulmonary tuberculosis in a rural endemic area of Bangladesh

Int J Mycobacteriol. 2014 Jun;3(2):88-93. doi: 10.1016/j.ijmyco.2014.03.003. Epub 2014 May 2.

Authors

Mohammad Tariqul Islam¹, Fazle Rabbi², Shameema Ferdous³, Ummey Shahnaz Parvin⁴, Akram Hossain⁵, Mohammad Sorowar Hossain⁶

Affiliations

¹ Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. Electronic address: ronyyoga@gmail.com.
² Microbiology Program, Department of Mathematics and Natural Sciences, BRAC University, Dhaka, Bangladesh. Electronic address: fazle@bracu.ac.bd.
³ Department of Microbiology, University of Dhaka, Dhaka, Bangladesh. Electronic address: shameemaferdous@yahoo.com.
⁴ Department of Microbiology, East West Medical College, Dhaka, Bangladesh. Electronic address: rupammc@gmail.com.
⁵ Department of Microbiology, Mymensingh Medical College, Mymensingh, Bangladesh. Electronic address: akram.prof@gmail.com.
⁶ Microbiology Program, Department of Mathematics and Natural Sciences, BRAC University, Dhaka, Bangladesh. Electronic address: sorowar.hossain@bracu.ac.bd.

PMID: 26786329
DOI: 10.1016/j.ijmyco.2014.03.003

Abstract

Objective: Bangladesh is a high tuberculosis burden country. It is always challenging to diagnose active pulmonary tuberculosis (PTB) cases in rural areas where the setting up of conventional microscopic and cultural diagnostic tools is difficult. The objective of the present study is to find a feasible, reliable and easily accessible alternative diagnostic approach for PTB in the rural areas of Bangladesh.

Methods: A total of 86 sputum samples were collected from clinically suspected PTB patients of Anantapur village, an underdeveloped remote area of Netrokona district, Bangladesh. Sputum samples were screened by Ziehl-Neelsen (Z-N) and fluorescence staining methods and were categorized as smear-positive active PTB cases (n=50) and smear-negative controls (n=36); then the performance of three popular immunological tests were evaluated, including ICT, ELISA and Mantoux tests (MT).

Results: The sensitivity of ICT, ELISA, and MT (10mm induration size) was 68%, 84% and 96%, respectively, and the specificity of these tests was 94.4%, 80.6% and 52.8%, respectively. When the cut-off size of induration in MT was changed from 10 to ⩾15mm, the sensitivity and specificity of MT became 92% and 83.3%, respectively. It was also found that the interpretation of MT was not significantly affected by BCG vaccination when ⩾15mm induration was taken as a cut-off value.

Conclusion: Considering the resource-constraints of rural and remote areas, the Mantoux test could be an alternative tool for the diagnosis of active PTB.

Keywords: Bangladesh; Immunological tests; Pulmonary tuberculosis.