Resumo das principais metodologias utilizadas no diagnóstico laboratorial da tuberculose, com ênfase na dosagem de adenosina deaminase (ADA) e estudo de influência do HIV nessa dosagem

Abstract

Objectives: To evaluate the real utility of the determination of pleural fluid adenosine deaminase (ADA-PF) activity in pleural tuberculosis diagnostic (TB pl), with special attention to the HIV coinfection. Methods: A retrospective protocol was performed by analyzing medical relatories of 40 patients from the Santa Maria University Hospital (SMUH), between January 2002 from January 2004. The necessary condition to include these individuals in the study was to present ADA-PF activity and HIV serologic research. Patients were divided in four different groups - group I : TB+ e HIV+; group II: TB+ e HIV-; group III: TB- e HIV+; group IV: TB- e HIV-. Among the 40 patients, 16 presented TB pl. It is important to state that, among this 16 patients, 37,5% also presented HIV infection. On the other 24 patients, the pleural effusion was occasioned by other etiologies. The analysis of ADA-PF was measured based on Giusti’s colorimetrical method. Results: The mean (S.E.) values of ADA-PF activities were 78.4 (25), 76.9 (15.8), 25.0 (13.3), and 16.0 (3.1) U/L for groups I, II, III, and IV, respectively. When HIV infection was not considered in the statistical analysis, the ADA-PF activity was significantly higher in tuberculosis patients when compared to patients with pleural effusion caused by other etiologies. Using a cut off value of 60 U/L, the found sensibility and specificity were 69,5% and 91,6%, respectively. The calculated Positive Predictive Value (PPV) was 89% and the Negative Predictive Value (NPV) was 80%. Conclusion: The measurement of ADA-PF activity represent an useful tool in the diagnostic of TB pl. In addition, the diagnostic value of ADA-PF seems to be independent on HIV serologic status.