Evaluation of glutaraldehyde test in the diagnosis of pulmonary tuberculosis in Nigeria

Abstract

In the developing world with scarcity of diagnostic facilities, the diagnosis of pulmonary tuberculosis (PTB) could often be difficult. Previous methods have proved inadequate, especially where TB is endemic. Serologic tests for the diagnosis of TB require advanced technology which is not readily available. The study therefore proposed to evaluate the usefulness (or otherwise) of the glutaraldehyde test (GT) in the diagnosis of PTB in this environment. Two hundred and ten consecutive consenting adults 18 years and above with newly diagnosed sputum smear positive PTB attending 4 government hospitals in the Lagos area were studied over one year. Age and sex matched controls from LUTH who had no symptoms or signs of TB were also studied. All cases had sputum smear examination (by the Ziehl-Neelsen method) and the glutaraldehyde test. Considering the normal gelification time of <215 seconds (at 1 SD), the glutaraldehyde test had a sensitivity, specificity, positive and negative predictive values of 92.40%, 90.50%, 90.65% and 90.20% respectively. However, when readings were taken at <85 seconds (2 SD), the sensitivity dropped to 74.80%, while the specificity increased to 100%. Both the false positive (7.6%) and false negative (9.50%) rates are low. The GT was also found to be much chapter than all others in the diagnosis of TB. HIV infection was found in 11 (7.19%) of the study population. The GT has appeared to be of diagnostic value in humans with sputum smear positive TB. However, that will include patients with smear negative disease should be conducted so that its applicability could be widened.

Keywords: pulmonary TB, sputum smear positive, glutaraldehyde test, Nigerians

Nigerian Journal of Health and Biomedical Sciences Vol. 4(2) 2005: 176-182