Evaluation of diagnostic assays for tuberculosis (TB) and formulation of a feasible testing strategy for rural areas of Pakistan

Abstract

Pulmonary tubercle bacillosis (PTB) is a highly prevalent infectious and lethal disease worldwide. To overcome this problem, a proper and feasible diagnostic protocol is required to diagnose the TB-infected persons particularly in hot rural areas wherein the disease incidence is expected to be high, e.g., the east Punjab region of Pakistan. This study was performed to identify the hidden cases so as to avoid further transmission of TB in the area. The most common procedures employed for the diagnosis of TB were Myco-Dot, ZN smear, Fluorescence microscopy, Mantoux test, and GeneXpert. A total of 259 samples of suspected patients were subjected to each of the earlier-mentioned protocols and compared with the gold standard TB culture method. By doing this it was possible to identify a good sensitivity- and specificity-based assay which would be easily available at an affordable cost by the common people. The GeneXpert test showed 81.1% sensitivity and 95.6% specificity, being higher with those determined by the other tests. However, this approach is cost-intensive and out of reach for the Punjab rural communities. Fluorescence microscopy was ranked second in its sensitivity (64.5%) and specificity (96.4%), since this method is relatively cost-effective, but not as much as the other methods already in vogue.