The TEG® assay does not replace measurements using plasma fibrinogen concentration. (Image source: Thinkstock)

The TEG® assay does not replace measurements using plasma fibrinogen concentration. (Image source: Thinkstock)

Fibrinogen is needed for adequate hemostasis.  Intraoperatively, thrombelastography (TEG®) is used to help rapidly measure fibrinogen concentration.  Is it accurate?

Dr. Anna Ågren, Department of Medicine, Division of Haematology, Coagulation Unit, Karolinska University Hospital, Stockholm, Sweden and Department of Clinical Sciences, Karolinska Institutet, Danderyd Hospital, Stockholm, Sweden, and colleagues had doubts whether TEG® measurements were accurate in patients with ongoing bleeding.  They compared functional fibrinogen concentration measured by TEG® with plasma fibrinogen concentration determined by the Clauss method. The results of their study appear in this month’s edition of Anesthesia & Analgesia in the article titled “TEG®Functional Fibrinogen Analysis May Overestimate Fibrinogen Levels.

Sixty-three patients with trauma or surgery with ongoing bleeding were studied. Patients did not receive colloid therapy.  Thirty-eight healthy blood donors served as controls. Each had venous blood samples analyzed for TEG®functional fibrinogen and fibrinogen plasma concentration.  in both patients and controls, TEG®functional fibrinogen was on average 1.0 g/L higher than the plasma fibrinogen concentration (3.5 versus 2.5 g/L).  Neither removing two outliers with high TEG® functional fibrinogen values, analyzing patient and control values separately, nor separating anemic from nonanemic patients affected the observation that fibrinogen levels were consistently overestimated when determined by TEG®.

This study provides clear evidence that certain abnormally low fibrinogen values might be missed if TEG®measurements alone are used.