[Diagnosis in sarcoidosis. Sensitivity and specificity of 67-gallium scintigraphy, serum angiotensin converting enzyme levels, thoracic radiography and blood lymphocyte subpopulations].

In a prospective study in 73 patients (48 female, 25 male) with histologically proven sarcoidosis we examined the sensitivity and specificity of Gallium 67 scanning, S-ACE, chest X-ray and blood T-lymphocyte assays for assessment of activity in sarcoidosis. We found a positive correlation between 67Ga score and S-ACE (r = 0.54, p less than 0.001). S-ACE levels and 67Ga score were significantly higher (p less than 0.001) in active sarcoidosis compared to inactive sarcoidosis. However, patients characterized by bihilar active sarcoidosis proved to have higher mean S-ACE levels (p less than 0.025) and a higher 67Ga score (n. s.) compared to patients with other presentations of active sarcoidosis. 67Ga scanning had the highest sensitivity of all parameters (92%) to detect active sarcoidosis, followed by chest X-ray (79%) and S-ACE (70%). Blood T-lymphocyte assays without comparison to lavaged lung T-lymphocytes failed to give reliable results. In patients with inactive sarcoidosis S-ACE showed a higher specificity (85%) compared to 67 Ga scanning (77%). Among follow up assessments in 26 patients with recurrent sarcoidosis 67Ga scanning proved to be the most reliable means for all stages of sarcoidosis whereas in patients with interstitial pulmonary lesions chest X-ray as well as S-ACE sometimes failed to assess activity. For the clinical management of patients with pulmonary sarcoidosis we suggest the combined use of chest X-ray and S-ACE. In case of discrepant results, as well as interstitial pulmonary involvement or for difficult therapeutic decisions the use of 67Ga scanning or bronchoalveolar lavage should be considered.