67Ga scintigraphy, using a 67Ga accumulation score, was compared with serum lysozyme (LZM) and angiotensin-converting enzyme (ACE) levels in 34 patients with biopsy-proven, pulmonary sarcoidosis. Serum LZM and ACE values varied between 1.0 to 21.3 mg/l (mean 4.3 +/- 3.4 mg/l) and 33 to 146 U/l (mean 69 +/- 26 U/l), respectively. Normal values were found in 26 and 35% of the patients. All patients, however, had abnormal 67Ga uptake in the pulmonary hilar lymph nodes and/or parenchyma. The follow-up of untreated and treated patients supports the suggestion that 67Ga scintigraphy is more useful for assessing the extent and activity of the intrathoracic sarcoid lesions. Serum LZM and ACE measurements are helpful, but normal LZM and ACE values do not exclude activity and progression of disease in pulmonary sarcoidosis.