Serum angiotensin-converting enzyme for diagnosis and therapeutic evaluation of sarcoidosis.

We have expanded our studies evaluating the usefulness of serum angiotensin-converting enzyme assays for supporting a diagnosis of active sarcoidosis. Increased concentrations (>35 units/ml, >2 SD above the mean for normal control subjects) were found in 57.8 per cent of 391 patients with sarcoidosis; 23.3 per cent of these patients were either receiving corticosteroid medication or had a diagnosis of inactive or resolved disease and had normal serum angiotensin-converting enzyme activity. Thus, 75.3 per cent of the patients with active, untreated disease had increased serum concentrations of angiotensin-converting enzyme. Serum concentrations of angiotensin-converting enzyme tended to be higher in blacks with sarcoidosis than in whites with sarcoidosis. Pediatric control subjects had higher concentrations of angiotensin-converting enzyme than adults; values greater than 50 units/ml were required for the concentration to be considered to be significantly increased. Patients placed on steroid therapy had s...