Purpose: To evaluate the role of combined serum angiotensin-converting enzyme (ACE) activity and whole-body gallium ( 67 GA) scanning in diagnosing sarcoidosis in patients with features consistent with ocular sarcoidosis but with normal or equivocal chest radiographs. Methods: Serum ACE levels and whole-body 67 GA scans were obtained as part of the initial workup in 22 patients with active ocular inflammation and ultimately biopsy-proven sarcoidosis (sarcoid uveitis group). A second group consisting of 70 patients with active uveitis in whom sarcoidosis also was considered a diagnostic possibility also was studied. All 70 patients ultimately had a definitive diagnosis other than sarcoidosis (nonsarcoid uveitis). All patients in this group also had a serum ACE and whole-body 67 GA scan performed as part of their initial investigations. Results: All patients in the sarcoid uveitis group had either an elevated ACE level or an abnormal scan. In 16 of the 22 patients, results of both tests were abnormal. In no patient in the nonsarcoid uveitis group were results of both tests abnormal. The sensitivity of an elevated ACE in diagnosing sarcoidosis was 73% and the specificity was 83%. Using the combination of a positive 67 GA scan and an elevated ACE, the specificity for diagnosis was 100% and the sensitivity was 73%. Conclusions: The combination of serum ACE level and whole-body 67 GA scan increases the diagnostic specificity without affecting sensitivity in patients with clinically suspicious ocular sarcoidosis who have normal or equivocal chest radiographs.
