ELEVATED NEGATIVE PREDICTIVE VALUE OF ANG IOTENSIN-CONVERTING ENZYME (ACE) IN THE DIAGNOSIS OF ACTIVE SARCOIDOSIS

Objective. To evaluate the usefulness of angiotensin converting enzyme (ACE) in the differential diagnosis of active sarcoidosis in action w ith other interstitial and granulomatous processes. Methods. The study involved 30 patients with a histological diagnosis of sarcoidosis, 38 subjects with anatomopathologically and/or tuberculosis, and 12 subje cts with idiopathic pulmonary fibrosis confirmed by histological studi es. Following the technique developed by Rohatgi and Ryan, a radioenzy matic system was used to determine the activity of serum ACE. In patie nts with sarcoidosis, levels of ACE were measured in active cases as w ell as those in remission. Our laboratory reference values for those o ver 20 years of age are 39.84+/-9.19 mumol/min/l. Results. Levels of A CE were significantly higher (p<0.001) in active sarcoidosis (67.71+/- 17.73 mumol/min/l) than during inactivity (41.18+/-16.00 mumol/min/l), tuberculosis (46.99+/-13.65 mumol/min/l), or fibrosis (35.87+/-11.36 mumol/mol/l). A cut-off point of 59 mumol/min/l shows a significant as sociation with the diagnosis of active sarcoidosis (p<0.001) and reach es a negative predictive value Of 90.90%. Conclusion. The usefulness o f serum ACE in the differential diagnosis of sarcoidosis should be rec onsidered.