title: ADA1/ADAp ratio in pleural tuberculosis: an excellent diagnostic parameter in pleural fluid.
abstract: We analysed the efficacy of pleural adenosine deaminase (ADAp) and the ADA1/ADAp ratio in the diagnosis of pleural tuberculosis in 103 pleural effusions, 27 of which were tuberculosis (TB) and 76 other diagnoses (non-TB). Smears, cultures and pleural biopsies were carried out in all cases, and were used for final diagnosis. The diagnostic yield of the parameters under study were as follows: smears/cultures of mycobacteria in fluid 11.1%/33.3%; biopsy 33.3%/51.8% and tuberculosis granulomas 85.1%. The levels of ADAp and ADA1/ADAp ratio in TB and non-TB groups showed very significant differences (P < 0.00001); in the TB group: ADAp 54.7 +/- 23.5 IU and ADA1/ADAp 0.27 +/- 0.08; in the non-TB group: ADAp 18.3 +/- 43.2 IU and ADA1/ADAp 0.64 +/- 0.14. The assay established ADA levels in pleural fluid > or = 40 IU and an ADA1/ADAp ratio < or = 0.42 as cut-off levels to identify individuals in the TB group, with a sensitivity of 88.8%/100%, a specificity of 92%/98.6%, a positive predictive value (PPV) of 80%/96.4%, a negative predictive value (NPV) of 95.8%/100% and an accuracy of 91.2%/99.02%. The ADAp levels in 27 patients with TB, showed close correlation with the number of monocyte macrophages (P = 0.001), but not with the number of lymphocytes (P = n.s.). The ADA1/ADAp ratio overcomes the limitations of ADAp (false positives and negatives), and is the most useful parameter for diagnosis on account of a high diagnostic yield, low cost and speed of the assay for identifying a pleural tuberculosis diagnosis, when compared with traditional methods.
authors.affiliation: Pneumology Department Ramón Y Cajal Hospital (Alcalá de Henares University), Madrid, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Pérez-Rodríguez
authors.forename: I J
authors.initials: IJ
authors.lastname: Pérez Walton
authors.forename: J J
authors.initials: JJ
authors.lastname: Sanchez Hernández
authors.forename: E
authors.initials: E
authors.lastname: Pallarés
authors.forename: J
authors.initials: J
authors.lastname: Rubi
authors.forename: D
authors.initials: D
authors.lastname: Jimenez Castro
authors.forename: G
authors.initials: G
authors.lastname: Diaz Nuevo
mesh_terms: D000243:Adenosine Deaminase / Q000032:analysis*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001431:Bacteriological Techniques; D015415:Biomarkers / Q000032:analysis; D004796:Clinical Enzyme Tests; D005260:Female; D006801:Humans; D007527:Isoenzymes / Q000032:analysis; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000201:enzymology* / Q000209:etiology / Q000473:pathology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis*
chemical_list: D015415:Biomarkers; D007527:Isoenzymes; D000243:Adenosine Deaminase