Cryoglobulin Lab

Cryoglobulins are circulating proteins, specifically immunoglobulins (i.e., IgG, IgM, IgA or light chains), that clump together (precipitate) when they are exposed to cold and dissolve when warmed. They may be present in small quantities in the blood of some healthy people but are most frequently associated with abnormal protein production and a variety of diseases and conditions. This test detects and measures the relative quantity of cryoglobulins in the blood.

Precipitated cryoglobulins can slow the flow of blood and block small blood vessels. The presence of large amounts of cryoglobulins in the blood, called cryoglobulinemia, can cause symptoms such as bruising, rashes, joint pain, weakness, and Raynaud phenomenon – pain, paleness, bluing, numbness, tingling, and coldness in the fingers and toes with exposure to cold. (These symptoms can also occur in people who do not have cryoglobulinemia.) Cryoglobulins can cause tissue damage that leads to skin ulcers and, in severe cases, to gangrene. They can activate the immune system, leading to the deposit of immune complexes in tissues, and cause inflammation, bleeding, and clotting that can affect circulation in organs such as the kidneys and liver.

There are three types of cryoglobulinemia:

• Type I, which consists of a monoclonal immunoglobulin – a single type of protein that is produced by an abnormal cloned cell. This type is often seen in people with myeloma or lymphoma.
• Type II, which consists of a mixture of monoclonal and polyclonal immunoglobulins. This type is often seen in people with hepatitis C or other viral infections.
• Type III, which consists of polyclonal immunoglobulins. This type is often seen in people with autoimmune diseases.

This test does not distinguish between these three types of cryoglobulins. Further testing can distinguish different types if this test is positive.