The Diagnosis of Sarcoidosis

A diagnosis of sarcoidosis should usually be supported by demonstration of sarcoid granulomas in an excised tissue or Kveim nodule. Kveim test material has not been readily available to American physicians due to difficulties in production of splenic extracts that are potent, specific, and stable. Kveim reactions occur most consistently in patients whose sarcoidosis is manifested by erythema nodosum. It is also valuable in other fresh cases with few or no symptoms; an unequivocal Kveim reaction may be obtained in 60 to 80% of such patients, making hospitalization for biopsy procedures unnecessary. The test is less useful in hospitalized patients. Biopsy procedures developed in recent years more rapidly and more consistently provide histologic evidence of sarcoidosis. Atypical sarcoidosis may be difficult to distinguish from unusual mycobacterial or fungal disease, but emphasis on pitfalls that are rarely encountered should not obscure the fact that with careful study accurate diagnosis is achieved in most cases. Greater precision is unlikely until the active fraction in Kveim test material is identified or the cause of sarcoidosis discovered.