Cryoglobulin, Qualitative, Serum
Cryoglobulin, Qualitative With Quantitative Reflex
Cryoglobulins may be present in macroglobulinemia of Waldenström, myeloma, chronic lymphocytic leukemia, lupus, chronic active hepatitis, and other viral infections.
These are proteins that precipitate from blood at low temperatures. A precipitate from serum that forms overnight at 4°C and dissolves at 37°C is called a cryoglobulin.
Cryoglobulins may be divided into three classes. Type I are monoclonal immunoglobulins and are usually associated with lymphoproliferative disorders. Type II are mixtures of a monoclonal IgM and polyclonal IgG, and are associated with macroglobulinemia and chronic active hepatitis. Type III are mixtures of polyclonal IgM and polyclonal IgG. These are found in a wide variety of disorders.
A high percentage of patients with cryoglobulinemia have clinical symptoms, and of these the most common are vascular (ie, purpura and digital necrosis). Raynaud phenomenon is also common.
Patients with SLE who are rheumatoid factor-negative but cryoglobulin-positive are more likely to develop renal disease than those who are rheumatoid factor-positive and cryoglobulin-negative.
Red-top tube (no gel)
Patient should be fasting.
Specimen must be drawn in a prewarmed tube and kept at 37°C while clotting. Separate serum from cells immediately after clot formation (keep at 37°C while clotting), and transfer serum into a clean transport tube. Label transport tube “Prewarmed.”
Specimen not allowed to clot at 37°C; patient not fasting; lipemia; gel-barrier tube used for collection; whole blood received