Cryofibrinogen

*Draw 3 light blue tubes. Keep tubes warm in heal warmer and bring to processing ASAP.
*Collect specimen Monday through Friday only before 1600 EST. Do not collect the day before a holiday.

376

LAB569

6 mL fasting plasma collected in each of three 3.2% sodium citrate (light blue-top) tubes

3 mL

Fasting plasma collected in each of three EDTA (lavender-top) tubes

Collect blood into three 3.2% sodium citrate (light blue- top) tubes or three EDTA (lavender-top) tubes and place immediately in a 37° C water bath, oven, incubator, heat block or heel warmer(s) for 1 hour. It is very important that the specimen remain at 37° C until after separation of plasma from red cells.

Centrifuge the specimen for 10 minutes at 1600 RCF (G) or at top speed utilizing one of the 3 options below:
1.) In a "warm" centrifuge at 37° C.
2.) In a bench-top centrifuge placed in a "warm room" at 37° C.
3.) At room temperature, in a bench-top centrifuge prewarmed by running it for 10 minutes at 1600 RCF (G) or at top speed.
After centrifuging, decant plasma into a screw-cap vial. Transport at room temperature.
Do not refrigerate or freeze.
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Note: If the sample is not kept at 37° C during all processing steps, the cryoprecipitate, if present, can precipitate out of solution and be lost during the centrifugation process and result in a false negative result.

Note: No tests can be added or poured off this tube; for cryofibrinogen evaluation only.

Transport tube(s)

Room temperature

Room temperature: 7 days
Refrigerated: Unacceptable
Frozen: Unacceptable

Gross hemolysis • Grossly lipemic • Heparinized plasma • Grossly icteric

Sun-fri

Negative

Cryofibrinogens are cryoproteins that precipitate only in plasma and not in serum when exposed to temperatures below 37° C and dissolves upon rewarming. Cryofibrinogens can occur independently or in association with cryoglobulins. Cryofibrinogens are composed of fibrinogen, fibronectin and fibrin but may also contain albumin and/or immunoglobulins. Fibrin and fibronectin are needed to induce the formation of cryofibrinogen and cold precipitation. In isolated Cryofibrinogenemia, the precipitate rarely contains immunoglobulins. However, when cryofibrinogenemia, is associated with cryoglobulinemia, the characteristic components of Cryofibrinogen contain polyclonal immunoglobulins in 80% cases and show a pattern similar to cryoglobulins. Cryoprecipitates in the serum are considered as positive cryoglobulins and cryoprecipitates in the plasma are positive as the sum of cryoglobulins and cryofibrinogens, both tests should be always performed simultaneously for differentiation.