[Angiotensin converting enzyme in lung diseases].

The aim of the study was to test the validity of ACE-determination for the differential diagnosis of pulmonary diseases. First details of the method, then the determination of the reference scale are discussed. The ACE-activity in the serum in 60 patients with sarcoidosis and 80 patients with other pulmonary diseases was measured. The sensitivity with which sarcoidosis can be established by means of the ACE-activity is to be examined. No positive correlation between the activity of the enzyme and the x-ray staging could be established, but active diseases requiring treatment could be distinguished from inactive forms to an unexpectedly high degree of reliance in our group of patients. The fact that in some cases of other pulmonary diseases--especially those connected with hepatopathy--higher ACE-activity is found as well, reduces the validity of the method. The determination of ACE comes up to all the criterias of a feasible, clinical-chemical method of analysis: practicability, reliance, high sensitivity and accuracy in a selected group, easy repetition. In some cases a typical x-ray result and corresponding clinical examination may provide the diagnosis of active sarcoidosis without further invasive methods of investigation; observation of the course of disease and adjustment of therapy are possible by means of the control of the ACE.