<unk>  and<unk>  disease must be distinguished from cryofibrinogenemia or cryofibrinogenemic disease, conditions which involve the cold-induced intravascular deposition of circulating native fibrinogens. These molecules precipitate at lower temperatures (e.g., 4 °C). Since cryofibrinogens are present in plasma but greatly depleted in serum, precipitation tests for them are positive in plasma but negative in serum. Cryofibrinogenemia is occasionally found in cases of<unk>  disease.<unk>  disease must also be distinguished from frostbite as well as numerous other conditions that have a clinical (particularly cutaneous) presentation similar to<unk>  disease but are not exacerbated by cold temperature, e.g., dysfibrinogenemia and dysfibrinogenemic disease (conditions involving the intravascular deposition of genetically abnormal circulating fibrinogens), purpura fulminans, cholesterol emboli, warfarin necrosis, ecthyma gangrenosum, and various hypercoagulable states. Rheumatoid factor is a sensitive test for<unk> . The precipitated cryoglobulins are examined by immunoelectrophoresis and immunofixation to detect and quantify the presence of monoclonal IgG, IgM, IgA, κ light chain, or λ light chain immunoglobins. Other routine tests include measuring blood levels of rheumatoid factor activity, complement C4, other complement components, and hepatitic C antigen. Biopsies of skin lesions and, where indicated, kidney or other tissues can help in determining the nature of the vascular disease (immunoglobulin deposition,<unk>  vasculitis, or, in cases showing the presence of cryfibrinogenemia, fibrinogen deposition. In all events, further studies to determine the presence of hematological, infections, and autoimmune disorders are conducted on the basis of these findings as well as each cases clinical findings.
Cryoglobulinemia
Myoglobinuria
Hemoglobinuria
Hemosiderinuria
Trimethylaminuria
Lipiduria
Pentosuria
Xanthinuria