There are 17 sets of diagnosis/classification criteria for Behcet's disease: Curth (1946), Hewitt (1969), Mason (1971), Japan (1972), Hubault (1974), O'Duffy (1974), Cheng (1980), Dilsen (1986), Japan revised criteria (1988), International Study Group on Behcet's disease (ISG criteria, 1990) . ISG criteria has very good specificity, but lacks good sensitivity and accuracy. In contrast, ICBD has much better sensitivity, a little less specificity and better accuracy.