Evaluation of Commercial Rapid Diagnostic Test Kit for Tuberculosis: Further Evidence Supporting Negative Policy on the Use of Serological Tests for Pulmonary Tuberculosis Diagnosis in Developing Countries

Aim: To know whether one of the commercially available immunochromatographic tuberculosis tests is comparable with the widely available method, direct sputum microscopy.
Design: The study prospectively validated the pulmonary tuberculosis rapid test kit using the reference standard, Lowenstein Jensen culture and compared the outcome with the direct sputum microscopy.
Place and Duration: The study was conducted in Zankli Medical Centre, Abuja, between November 2004 and July 2005.
Methodology: 340 patients from direct observation therapy clinics located in six different government owned health facilities were referred to our facility. These patients; male (192) and female (148) were between the age of 10 and 64 years old. Three sputa samples were collected over two consecutive days and direct microscopy and culture were performed on these samples. Also, 4ml of blood were collected from the same patients for antibody detection using immunochromatographic technique.
Results: The evaluated rapid diagnostic kit when compared with the reference standard has a sensitivity of 59.3% and 81.1% specificity. Sensitivity and specificity of direct microscopy, when compared with the rapid test is statistically significant (P=0.001); indicating diagnostic accuracy of the conventional method of pulmonary tuberculosis testing over the immunochromatographic test.
Conclusions: The conventional test indicated high performance in this report and it is suggestive of the relevance and diagnostic accuracy of the widely available method in the diagnosis of pulmonary tuberculosis in developing countries. This assertion is also, supported by the 2008 WHO/TDR report on evaluation of nineteen tuberculosis rapid diagnostic kits