A comparative study of fibrinogen measurement using TEG® functional fibrinogen and Clauss in adolescents undergoing scoliosis surgery.

Abstract

Thromboelastography (TEG®) functional fibrinogen (FF) test is a point-of-care test for fibrinogen measurement and is preferred for its rapid turnaround time. This study was designed to compare TEG® functional fibrinogen level (FLEV) with classic Clauss fibrinogen in patients undergoing scoliosis surgery and to evaluate the concordance between the two methods. Patients in this study were part of a larger study evaluating the effect of fibrinogen concentrate (FC) supplementation on perioperative blood loss in scoliosis surgery. Paired samples for TEG® FF and Clauss fibrinogen assays were taken from 40 patients at three different timepoints perioperatively. The agreement between FLEV and Clauss was assessed, and the possibility of using FLEV measurements to predict Clauss fibrinogen was explored. One hundred and seventeen paired samples from 39 patients were finally analyzed. Pearson correlation test confirmed positive linear correlations between FLEV and Clauss at all three timepoints (r=.70, .67, and .66 at baseline, before FC administration, and after FC administration, respectively; P<.001 for all) and together for all measures (r=.76, P<.001), while Bland-Altman plots showed FLEV significantly overestimated Clauss constantly. Optimum diagnostic values of FLEV at 4.27 and 3.77g/L were generated to predict normal fibrinogen as Clauss≥3.0g/L (AUROC 0.941, 95% CI: 0.891-0.991) and critical intraoperative hypofibrinogenemia as Clauss≤2.0g/L (AUROC 0.894, 95% CI: 0.838-0.950), respectively. In adolescents undergoing scoliosis surgery, FLEV correlated linearly with Clauss fibrinogen. Though FLEV overestimates Clauss constantly, FLEV values are able to predict hypofibrinogenemia and normal fibrinogen with both AUROC>0.85.