Cerebrospinal fluid adenosine deaminase and lysozyme levels in the diagnosis of tuberculous meningitis.

Selvakumar, N.; Vanajakumar; Duraipandian, M.; Thillothammal, N.; Prabhakar, R.

Indian Journal of Tuberculosis; 1991; 38; 217-220.

Adenosine Deaminase Activity (ADA) and Lysozyme Activity (LYSA) were measured in the CSF of tuberculous meningitis (TBM) cases : 26 bacteriologically positive TBM (Group 1), 61 bacteriologically negative TBM (Group 2), 10 non-tuberculous meningitis (Group 3) and 17 control subjects (Group 4). The mean ADA levels in different groups in that order were found to be 11.6, 4.5, 4.4 and 0.8 U/l respectively. The mean LYSA levels in the same groups were 6.3, 2.1, 2.2 and 0.5 mcg/ml respectively. In bacteriologically positive TBM, the mean ADA and LYSA levels were significantly higher than the other three groups (p < 0.0001). An ADA level of 4U/l and LYSA tests were 96%, 82% and 85%, 95% respectively. When both the criteria were considered, the sensitivity and specificity were 91% and 93% respectively. Combination of both test definitions could give additional support to the diagnosis in 49% of 61 clinically suspected but bacteriologically negative TBM cases. Correlation of ADA and LYSA levels in CSF was found to be statistically significant (r = 0.59; p < 0.01).


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