Assessment of activity in chronic sarcoidosis: usefulness of serum angiotensin converting enzyme and gallium scan.

Gallium scan and serum angiotensin converting enzyme (SACE) activity were performed in 39 patients, who were not receiving corticosteroids and had histologically proven chronic sarcoidosis of at least 2 years duration. Results of these investigations were compared with clinical assessment of disease activity. In patients with radiographic evidence of pulmonary parenchymal disease, the positive and negative predictive values for gallium scan and/or SACE were 96 and 100% respectively; however, in patients with no radiographic evidence of parenchymal disease the positive and negative predictive values were 50 and 100%, respectively. These findings suggest that SACE and gallium scan are useful in assessing the activity and hence the need for therapy in patients with chronic sarcoidosis with radiographic evidence of parenchymal disease.