Abstract

SAN MARTIN ACOSTA, VR  and  CATEDRA DE NEUMOLOGIA. HOSPITAL DE CLINICAS. FACULTAD DE CIENCIAS MEDICAS UNIVERSIDAD NACIONAL DE ASUNCION. Levels of activity of the enzyme adenosine deaminase in tuberculosis and non-tuberculosis pleural effusions. An. Fac. Cienc. Méd. (Asunción) [online]. 2011, vol.44, n.1, pp.17-28. ISSN 1816-8949.

ABSTRACT Introduction: Tuberculosis remains the major cause of pleural effusion, being the most frequent extrapulmonary tuberculosis and, to have the diagnosis is often necessary to make an aggressive technique, such as pleural biopsy, which has high performance. The characteristic granulomas can be found in up to 80% of cases and the culture of the sample, or repeat biopsy may be positive up to 90% of cases. Adenosine deaminase value below the cutoff point would almost certainly rule out the existence of pleural tuberculosis, on the contrary, a value of adenosine deaminase higher than the cutoff is less informative. Objective: To determine the adenosine deaminase activity in patients with pleural effusions caused by tuberculosis and other diseases as well as the cutoff for denosine deaminase in pleural fluid, that allows higher sensitivity for tuberculosis. Patients and methods: This diagnostic study included 106 subjects of both sexes with pleural effusion. To determine the cutoff point that allows higher sensitivity for the diagnosis of pleural tuberculosis, for the determination of adenosine deaminase it was used the Receiver Operating Curve. Results: In the case of patients with tuberculosis, all adenosine deaminase values ??were equal to or greater than 40U/L. Patients with transudates submitted adenosine deaminase values ??above 40U/L, and patients with pleural effusion for pneumonia or cancer, have had adenosine deaminase values ??above and below 40U/L. Considering as cutoff point, a value of adenosine deaminase activity equal to or higher than 40U/L, the sensitivity of the enzyme for the diagnosis of pleural tuberculosis was 100% (95% CI 98.4% - 100%) and specificity of 62.6% (95% CI 60.6% - 64.6%), and a negative predictive value presented a value of 1. Conclusion: Although the dosage sensitivity of adenosine deaminase was 100% for the diagnosis of pleural tuberculosis, the correlation of this test with the reference standard was only moderate. The impact diagnosis according to the negative likelihood ratio, can rule out pleural tuberculosis, if the level of adenosine deaminase in the pleural effusion of a patient without human immunodeficiency virus, is below 40U/L, being this is main use. Keywords: pleural tuberculosis, diagnostic test, adenosine deaminase

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