[The diagnostic usefulness of cholinesterase in pleural exudates].
OBJECTIVE
The pleural fluid/serum cholinesterase ratio (PF/S) is the most efficient parameter to differentiate transudates from exudates. The objective of this study was to evaluate whether its determination might yield additional diagnostic information in pleural exudates.


METHODS
A total of 167 patients with the diagnosis of pleural exudate were studied: 74 carcinomatous, 32 tuberculous, 31 parapneumonic, 30 other causes. Pleural fluids were divided on the basis of lymphocyte or polymorphonuclear predominance and were grouped according to diagnosis. The PF/S cholinesterase ratio was determined in all patient.


RESULTS
In lymphocytic exudates, when PF/S ratio was < 0.42 pleural effusion was classified as malignant, with a sensitivity (S) of 56% (95% CI: 43%-66%) and a specificity (SP) of 90% (95% CI: 78%-95%). For the diagnosis of tuberculosis, in the total of pleural effusions, a ratio > or = 0.45 showed a S of 97% (95% CI: 82%-99%) and a SP of 51% (95% CI: 42%-59%).


CONCLUSIONS
The PF/S cholinesterase ratio yielded an useful information on the diagnosis of pleural exudates. Thus, in our series of patients, a ratio < 0.42 in a lymphocytic effusion suggested a malignant origin, and a ratio < 0.45 practically ruled out tuberculosis, irrespective of the cellular predominance in the pleural fluid.
García Pachón
E
E
Servicio de Medicina Interna, Hospital Vega Baja, Orihuela.
Padilla Navas
I
I
D000328:Adult; D000368:Aged; D002802:Cholinesterases / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010996:Pleural Effusion / Q000737:chemistry / Q000175:diagnosis* / Q000209:etiology; D016066:Pleural Effusion, Malignant / Q000737:chemistry / Q000175:diagnosis / Q000209:etiology; D012680:Sensitivity and Specificity; D014396:Tuberculosis, Pleural / Q000175:diagnosis
D002802:Cholinesterases