26596 Cryoglobulin, Serum(CRY_S)

Evaluating cryoglobulins in patients with vasculitis, glomerulonephritis, and lymphoproliferative diseases

Evaluating cryoglobulins in patients with macroglobulinemia or myeloma in whom symptoms occur with cold exposure

This test is not useful for general screening of a population without a clinical suspicion of cryoglobulinemia.

1. Tube must remain at 37 degrees C. Keep tubes on heat pack. ​
   
2. Allow blood to clot at 37 degrees C.
3. Centrifuge at 37 degrees C. Do not use a refrigerated centrifuge. If absolutely necessary, ambient temperature is acceptable. It is very important that the specimen remain at 37 degrees C until after separation of serum from red blood cells.
4. Place serum into an appropriately labeled plastic vial.
   

Additional Information: Analysis cannot be performed with less than 3 mL of serum. Smaller volumes are insufficient to detect clinically important trace (mixed) cryoglobulins. Less than 3 mL will require collection and submission a new specimen.

​Failure to follow specimen handling instructions may cause false-negative results.​

​Cryoglobulins are immunoglobulins that precipitate when cooled and dissolve when heated. Because these proteins precipitate when cooled, patients may experience symptoms when exposed to the cold. Cryoglobulins may be associated with a variety of diseases including plasma cell disorders, autoimmune diseases, and infections. Cryoglobulins may also cause erroneous results with some automated hematology instruments.

Cryoglobulins may be classified as follows: Type I, Type II, and Type III. Type I is composed of a monoclonal immunoglobulin: IgG or IgM, or rarely IgA or free monoclonal light chains. Type II cryoglobulins consist of a monoclonal component and a polyclonal component. Finally, type III cryoglobulins are composed of only polyclonal immunoglobulins.

The majority of patients with cryoglobulins are asymptomatic. The type or quantity of cryoglobulin does not reliably predict whether or which symptoms will be present. The concentration of cryoglobulins tends to vary by type with the majority of cases: of type III, being less than 1 mg/mL; of type II, greater than 1 mg/mL; and of type I, greater than 5 mg/mL. Even though the type I cryoglobulin concentrations tend to be the highest, they are the least likely to cause symptoms. The thermal amplitude (temperature at which the cryoglobulin precipitates) is a better predictor of symptoms than quantity or type.

Symptoms of cryoglobulinemia include purpura, Raynaud phenomenon, cyanosis, skin ulceration, gangrene, kidney failure, peripheral neuropathy, fever, and malaise.

Type I cryoglobulinemia is associated with monoclonal gammopathy of undetermined significance, macroglobulinemia, or multiple myeloma.

Type II cryoglobulinemia is associated with autoimmune disorders such as vasculitis, glomerulonephritis, systemic lupus erythematosus, rheumatoid arthritis, and Sjogren syndrome. It may be seen in infections such as hepatitis, infectious mononucleosis, cytomegalovirus, and toxoplasmosis. Type II cryoglobulinemia may also be essential, ie, occurring in the absence of underlying disease.

Type III cryoglobulinemia usually demonstrates trace levels of cryoprecipitate, may take up to 7 days to appear, and is associated with the same disease spectrum as Type II cryoglobulinemia.

Negative (positives reported as percent or trace amount)

If positive after 1 or 7 days, immunotyping of the cryoprecipitate is performed at an additional charge.

​An interpretive report will be provided