Sensitivity and Specificity of TaqMan Real Time PCR, PCR, Microscopy and Culture in Diagnosis of Tuberculous Meningitis in a High Incidence of Tuberculosis Province in Southeast of Iran

The most dangerous form of extra-pulmonary tuberculosis is tuberculous meningitis (TBM). Diagnosis of TBM has special problem due to its paucibacillary. Also, sensitivity and specificity of routine microscopy and culture in the diagnosis of this disease is controversial. So, faster and more accurate laboratory test is required. Polymerase chain reaction (PCR) and real time PCR may be good candidates for this purpose. We did this study to compare sensitivity and specificity of TaqMan real time PCR, PCR, microscopy and culture in diagnosis of TBM. We had 49 patients with primary diagnosis of TBM during January 2007 and January 2008 in Bou-Ali University Hospital, Southeast of Iran. Combining and using the definite and probable TB as a gold standard, 29 of these patients had a final diagnosis of TBM. The extracted DNA of samples was applied for conventional PCR and TaqMan real time PCR. Our study showed that the sensitivity and specificity of TaqMan real time PCR was 96% and 95% respectively. These values were 89% and 90, 38% and 100%, 6% and 100% for PCR, culture and microscopy, respectively. Our study showed that sensitivity of TaqMan real time PCR was higher that PCR, culture and microscopy but specificity of culture and microscopy was more than PCR and even TaqMan real time PCR.