- Venous blood is needed.
- Keep the blood at 37 °C.
- Separate the serum at 37 °C, so the cryoglobulins remain in the serum.
- Maintain the temperature of the blood at 37 °C.
- Also, maintain the temperature of the serum at 37 °C.
Purpose of the test
- This test is done to diagnose:
- Raynaud phenomenon.
- These are immunoglobulins that precipitate reversibly at low temperatures.
- Most of the cryoglobulins are polyclonal immunoglobulin complexes, and nearly half are monoclonal, usually IgM.
- Cryoglobulins are abnormal immunoglobulins proteins produced due to various diseases.
- Cryoglobulinemia is defined as a condition in which plasma or serum proteins (IgM) precipitate when cooled below body temperature.
- These proteins precipitate at 4 °C and dissolve again at 37 °C.
- These are the proteins that reversibly precipitate or gel at 4 °C.
- These cryoglobulins are classified as follows:
- Type I (Monoclonal).
- Type II (This is mixed cryoglobulin, a mixture of polyclonal immunoglobulins).
- Type III (Polyclonal).
- Type I monoclonal cryoglobulins are produced by the neoplastic lymphocytes and plasma cells. These are typically IgM type of immunoglobulin.
- May see IgG as well.
- These may constitute 25% of the cryoglobulins.
- Associated with multiple myeloma, macroglobulinemia, and rare neoplasm of the plasma cells and lymphocytes.
- Type II cryoglobulins consist of two types:
- The monoclonal form is seen as the rheumatoid factor and usually is IgM with a kappa light chain.
- Second is polyclonal IgG which reacts with rheumatoid factor (IgM).
- Type III cryoglobulins are mixed cryoglobulins and two polyclonal immunoglobulins.
- More than 90% contains IgM. rheumatoid factor and IgG.
- Mostly seen in autoimmune diseases.
- There are circulating immune complexes produced by various antigens like viral, bacterial, and autologous antigens.
- Mixed cryoglobulinemia consists of type II and type III.
- Signs and symptoms:
- These proteins precipitate in the blood vessels of fingers when exposed to cold.
- These patients will have symptoms of:
- Vascular purpura.
- Bleeding tendency.
- Cold-induced urticaria.
- Raynaud phenomenon (pain, cyanosis, the coldness of fingers).
- These proteins are present in various diseases.
- Serum level > 5mg = Multiple myeloma, macroglobulinemia, and leukemia.
- Serum level between 1 to 5 mg = Rheumatoid arthritis.
- Serum level < 1mg = SLE, RA, infectious mononucleosis, viral hepatitis, endocarditis, cirrhosis, glomerulonephritis.
|Type of cryoglobulin||disease|
|Type I||Multiple myelomas, macroglobulinemia, monoclonal gammopathy.|
|Type II||Vasculitis, glomerulonephritis, SLE, RA, Sjogren’s syndrome, hepatitis, CMV.|
|Type III||May see diseases like type II, and autoimmune diseases.|
- The serum is negative for the cryoglobulins.
- Clotted blood is centrifuged at 37 °C.
- Keep the serum in the fridge at 4 °C.
- Keep it for at least 3 days and again centrifuge at 4 °C.
- Check the serum daily for white precipitate or gel.
- Check daily for at least 72 hours to 7 days.
- The precipitate is recorded and measured, which is cryoglobulin.
- Rewarm the sample if it dissolves, then it confirms the cryoglobulins.
- Cryoprecipitate is washed and subject to Immunoelectrophoresis is done to identify the type of cryoglobulin.
Causes of Cryoglobulins
- Autoimmune diseases like SLE, RA, Sjogren’s syndrome.
- Malignancies like Multiple myeloma, Leukemia, Waldenstrom macroglobulinemia, and Lymphoma.
- Acute and chronic infections like Infectious mononucleosis, Poststreptococcal glomerulonephritis, and endocarditis.
- Liver diseases like Cirrhosis and Hepatitis.
- Renal involvement manifests as either nephrotic or nephritic syndrome and associated with hypocomplementemia.
- The most common finding is membranoproliferative glomerulonephritis type II.