Cryoglobulins
- Description
- A cryoglobulin screen involves observation of a serum specimen collected and separated while warm for cryoprecipitation over a period of up to 7 days. Values of the screening may be reported as cryocrit, which is the volume percent of the precipitate compared with the total volume of serum. Further proof that the precipitate is indeed a cryoglobulin can be obtained by demonstrating resolubilisation with warming and immunochemical characterisation by immunofixation.
- Clinical details
Cryoglobulinaemia refers to the presence of cryoglobulins in the serum. Cryoglobulins are immunoglobulins that reversibly precipitate at temperatures below 37°C. There are three types:
Type l cryoglobulinaemia which is usually associated with lymphoproliferative disorders.
Types ll and lll may be associated with infectious (hepatitis C virus infection) or autoimmune disorders. The clinical presentation includes a triad of purpura, weakness, and arthralgia. Multi-systemic involvement may occur, particularly affecting the kidneys, liver, and nervous system. Widespread small vessel vasculitis has been also demonstrated. Testing for cryoglobulins is useful in patients with vasculitis, glomerulonephritis, and lymphoproliferative diseases. It is also helpful in patients with macroglobulinaemia or myeloma in whom symptoms occur with cold exposure.
- Related condition
- Reference range
Negative
Positive samples are reported as percent, then characterised into Type I, II or III cryoglobulinaemia.
- Synonyms
Cryoglobulin, cryofibrinogen, cryoprotein
- Testing site
- Synnovis : Reference Services : Blackfriars Hub
- Laboratory
- Diagnostic Immunology
- Sample type and volume required
Paired serum and plasma samples are required: Collect blood in one yellow top and one Lavender top (EDTA) tubes, at least 4 – 8 ml /tube. Patient should not be receiving anti-coagulation treatment prior to test.
- Call in advance
Yes
- Special sample instructions
Collect samples in pre-warmed syringe/vacutainer. Put samples in water-tight specimen bag then place tubes inside a Thermal flask containing 38-42 °C water. Failure to adhere to specimen handling instructions may cause false-negative results.
- Storage and transport
Samples must be kept and transported at 37ºC to the laboratory and should reach laboratory before 3 PM.
- Turnaround time
Turnaround time is 7 days from receipt. All new positive samples will require further 5-7days for further testing and characterisation. This may lead to a delay in the quoted turnaround time