Incubation of serum at 4 degrees C and 37 degrees C, positive cryoglobulins redissolved and further characterized. Interpretation of positive results is made by a pathologist. Cryocrit run on positive cryoglobulins to determine what percent of the serum is cryoglobulin.
Cryoglobulin detection. Cryoglobulins may be present in multiple myeloma, Waldenstrom's macroglobulinemia, lymphocytic leukemia, autoimmune diseases and hepatitis C infection.
Small amounts of fibrin may come out at both 4 degrees C and 37 degrees C and may mask trace amounts of cryoglobulin. Concentrations of less than 10 mg/dL (0.10 g/L) are probably not significant. Specimens MUST be maintained at 37 degrees C. Some cryoglobulins precipitate very near body temperature. Specimens not maintained at 37 degrees C may result in false negative results.
Preliminary results are reported in 48 hours; final results are reported in 7 days.
- CRYOGLOBULIN CHARACTERIZATION
- 48 HOURS
- 7 DAYS
Whole blood must be maintained at 37 degrees C +/- 2 degrees C from the time it is collected until serum is separated from the cells. Collect blood into prewarmed red top tubes (serum separator tube is unacceptable). Within one minute, specimen must be placed into a 37 degrees C +/- 2 degrees C incubator or waterbath. Leave specimen at 37 degrees C until clot retracts; blood may be left at 37 degrees C up to 24 hours. After the clot retracts, remove serum from clot, centrifuge at room temperature, and aliquot 5 mL cell free serum into two aliquot tubes (2.5 mL each). Please note on requisition or as a footnote in the computer that the specimen was processed at 37 degrees C. Keep serum specimen at ambient (room) temperature until delivered to MLabs. If specimen processing equipment is not available, the patient should have the specimen collected at a University of Michigan Taubman Center Blood Drawing station.
Place specimen in 37 degrees C Thermos containing a warm pack or waterbath immediately. See Collection Instructions below.
Positive cryoglobulins are further characterized at an additional charge (CRYOQ). By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated. Test may include pathologist interpretation of results at an additional charge. By ordering this test, the clinician acknowledges that a pathologist interpretation will be performed and billed as a separate additional charge if indicated. Cryoglobulins may be divided into 3 classes. Type I are monoclonal immunoglobulins and are usually associated with lymphoproliferative disorders. Type II are usually mixtures of a monoclonal IgM and polyclonal IgG and are often associated with hepatitis C infection. 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, i.e., purpura and digital necrosis. Raynaud's phenomenon is also common.