There is no specific "Behcet’s test". Consequently, the diagnosis is based on the clinical signs and symptoms that are compatible with the disease - such as the presence of oral/genital ulcers, uveitis and skin lesions, etc.


An international group of physicians has established a set of guidelines to aid in the classification of Behcet’s patients for the purpose of conducting research in the disease. The criteria put forth by the group include recurrent oral ulceration (at least three occasions in a year). In addition, a patient must also meet two of the following four criteria for Behcet’s disease: recurrent genital ulcerations, eye lesions (uveitis or retinal vasculitis), skin lesions (erythema nodosum, lesions, acne), and or positive "pathergy test".


The pathergy test is a simple test in which the forearm is pricked with a small, sterile needle. Occurrence of a small red bump or pustule at the site of needle insertion constitutes a positive test. Although a positive pathergy test is helpful in the diagnosis of Behcet’s, only a minority of Behcet’s patients demonstrates the pathergy phenomenon (i.e., have positive tests). Patients from the Mediterranean region are more likely to demonstrate pathergy. In addition, other conditions can occasionally result in positive pathergy tests, so the test is not 100% specific.