Application of PCR and Adenosine deaminase assay test for the diagnosis of tuberculous meningitis infection

Tuberculous meningitis is a medical emergency that low sensitivity of CSF smear staining and mycobacterial culture make its diagnosis difficult, so there is an urgent need for rapid, accurate and reliable laboratory test. The aim of this study was comparing the sensitivity and specificity of CSF adenosine deaminase (ADA) level with Polymerase Chain Reaction (PCR) test in the diagnosis of tuberculous meningitis (TBM). Methods and Materials: In the period between January 2007 and January 2008 we had 49 patients with primary diagnosis of TBM in Bou-Ali University hospital. After committing and using the definite and probable TB as a golden standard, the final diagnosis for 29 of them was TBM. Our study showed that the sensitivity and specificity of CSF-ADA level in comparison with PCR results in diagnosis of TBM with a 6.5 IU/L cut-off were 100% and 85% respectively. Our study showed that selecting a 6.5 IU/L cut-off with respect to the PCR results of the patients makes a reasonable sensitivity and specificity for CSF-ADA test in TBM diagnosis. Our study emphasized that CSF-ADA level measurement can be used as a good, rapid and reliable laboratory test for diagnosing tuberculous meningitis.