Coagulation laboratory tests

Cryoglobulin / cryofibrinogen assays

Last author update: 1 June 2012
Last staff update: 15 September 2020

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PubMed Search: Cryoglobulin assays OR Cryofibrinogen assays

Jeremy C. Parsons, M.D.
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Table of Contents
Definition / general
Cite this page: Parsons JC. Cryoglobulin / cryofibrinogen assays. website. Accessed June 3rd, 2023.
Definition / general
  • Either asymptomatic or causes cutaneous symptoms at cold - exposed areas
  • Cryofibrinogen consists of fibrinogen and other substances that precipitate at cold temperatures (cryoglobulins are immunoglobulins that precipitate at cold temperatures)
  • Either primary, or associated with malignancy, infection (especially hepatitis C), inflammatory conditions, diabetes, pregnancy, oral contraceptives
  • May exhibit leukocytoclastic vasculitis in skin biopsies

  • Specimen:
    • Two sodium citrate or EDTA tubes plus one red top tube for cryoglobulin
    • Place immediately in warm water (or use warmer for heal sticks or other warming method) and transport to laboratory within 2 hours
    • Dont use heparin - containing specimens (heparin precipitates fibrinogen in this assay)

  • Indication:
    • For patients with unexplained cutaneous ulcers or ischemia on cold - exposed areas

  • Procedure:
    • Centrifuge at 37C, refrigerate plasma, centrifuge at 4C
    • Each mm of visible precipitate represents 1% of cryofibrinogen
    • Cyrocrit is %volume of precipitate compared to total plasma
    • Also perform cryoglobulin test to ensure that plasma precipitate is not a cryoglobulin
    • If the cryoglobulin test is positive, serum protein electorpheresis with immune fixation should be run to determine what type of cryoglobulin is present
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