Cryoglobulins (CG) are immunoglobulins that reversibly precipitate from serum in cold temperatures. They are classified into three types, based on the monoclonality of the γ-globulins present (1 ): Type I contains only monoclonal bands; type II contains mixed polyclonal immunoglobulins with a monoclonal component; and type III contains mixed polyclonal immunoglobulins only.
