The clinical course of sarcoidosis is varying and unpredictable. Once the diagnosis has been made, the clinician needs simple tests to detect and predict remission or progression, to determine whether treatment is effective or not, and to assess the clinical activity of the disease. Sarcoidosis is a multisystem disease, but the lungs are almost always involved. Traditionally, the clinical management has therefore included chest X-rays and lung function studies. Extrapulmonary lesions have been followed in different ways. Sensitive and reproducible biochemical tests would be helpful in evaluating the clinical course of patients with sarcoidosis, if they measure functions related to the granulomatous inflammation. This review will deal with measurements of serum and urinary calcium, and 1,25-dihydroxyvitamin D. The usefulness of single and serial determinations of lysozyme, angiotensin converting enzyme, beta 2-microglobulin, collagenase, carboxypeptidase and glucuronidase in serum, bronchoalveolar lavage fluid, and other biological fluids will be discussed.