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All About Bleeding

Fibrinogen (Factor I) Deficiencies

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Two methods help diagnose fibrinogen deficiency:

  • Laboratory testing uses fibrinogen assays to measure plasma fibrinogen levels
  • Point-of-care methods provide rapid results. They are valuable in diagnosing and managing hemostasis disorders associated with high blood loss during and after surgery. 8

Laboratory tests

Clauss assay

This assay, considered to be the gold standard, measures the plasma fibrinogen concentration. Coagulation time is measured in a diluted plasma sample in the presence of a high concentration of thrombin. The fibrinogen level is inversely correlated with the clotting time.9-10 One flaw of this method is falsely elevated estimates of fibrinogen levels if high levels of degraded fibrin products are present. Samples containing colloids (e.g. gelatin or hydroxyethyl starch) may also contribute to this effect. This is an important consideration given that fluid resuscitation products contain such colloids.11-12

Immunological assays

These assays can detect very low levels of fibrinogen, but they do not evaluate the function of fibrinogen (e.g. those associated with afibrinogenemia or hypofibrinogenemia).10. A sample taken from a patient with dysfibrinogenemia would show normal or near-normal fibrinogen levels, but the fibrinogen would be dysfunctional and unable to form a stable hemostatic plug.

Point-of-care assays

Automated tests that perform whole blood assays include thromboelastography (TEG®) and rotation thromboelastometry (ROTEM®). Both TEG® and ROTEM® can assess the interaction of coagulation factors and platelet function, and measure the timing and activity of fibrin formation and clot development. An advantage of both TEG® and ROTEM® is that they can be located in emergency departments and operating theatres. They provide rapid and accurate diagnostic information, helping clinicians effectively manage blood loss.8

Last Updated: 10/10/2013 11:58 AM
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