Classification criteria that have been developed with an accepted statistical methodology are presently lacking for cryoglobulinemic syndrome or vasculitis (CV). However, they are essential for research and epidemiologic studies, and in turn for clinical practice. Earlier CV classification criteria were elaborated by individual experts or a panel of experts, such as those proposed in 1995 by the GISC (Italian Study Group on Cryoglobulinemia). New, albeit still preliminary classification criteria for CV were recently developed by a co-operative international study drawing upon a standardized methodology based on a large number of real cases/controls (n = 925). These criteria were subsequently shown to have a high specificity (93.6%) and good sensitivity (88.5%) for CV. Formal validation involving experts from a larger number of countries is now needed
