Association between Clauss fibrinogen concentration and ROTEM® FIBTEM

Authors: Gillissen, A.; Golyardi, B.; van den Akker, T.; Caram-Deelder, C.; Henriquez, D.

Affiliations: Centre for Clinical Transfusion Research, Sanquin Research, Leiden, the Netherlands. Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands. Department of Obstetrics, Leiden University Medical Center, Leiden, The Netherlands. Leiden University Medical Center, Leiden, The Netherlands. National Perinatal Epidemiology Unit, University of Oxford, Oxford, United Kingdom. Department of Obstetrics, Birth Centre Wilhelmina’s Children Hospital, University Medical Center Utrecht, Utrecht, The Netherlands. Division of Obstetrics and Prenatal Medicine, Department of Obstetrics and Gynaecology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Department of Hematology, Erasmus MC, University Medical Center Rotterdam, Rotterdam, The Netherlands. Department of Internal Medicine, Division of Thrombosis and Haemostasis, Leiden University Medical Center, Leiden, the Netherlands

Publication: medRxiv. 2023

Abstract: OBJECTIVE: Point-of-care tests like FIBTEM A5 have been proposed to guide the treatment of patients who might have low fibrinogen concentrations (≤2 g/L). The aim of this study was to describe fibrinogen concentrations according to previously proposed FIBTEM A5 cut-off points in blood samples collected from women during postpartum haemorrhage. DESIGN AND SETTING Prospective multicentre cohort study POPULATION 511 women sustaining postpartum haemorrhage. A total of 637 blood samples were drawn during haemorrhage. METHODS Clauss fibrinogen concentrations and ROTEM® FIBTEM A5 values were studied to assess the diagnostic properties of previously proposed FIBTEM A5 cut-off points for the detection of low fibrinogen concentrations. MAIN OUTCOME MEASURES Youden index, sensitivity, and specificity. RESULTS Of 511 women with a median total volume of blood loss of 1500 mL (IQR 1200 to 2000) 31 women (6%) developed Clauss fibrinogen concentrations below 2 g/L. Using FIBTEM A 5 cut-off of ≤ 7 mm: 48% of cases with Clauss fibrinogen ≤2 g/L were missed (FIBTEM A5 > 7mm), and of the 28 samples with FIBTEM A5 ≤ 7mm, 12 (43%) samples had Clauss fibrinogen >2 g/L. Using FIBTEM A5 cut-off of ≤12mm: 13% of cases with Clauss fibrinogen ≤2 g/L were missed and of the 145 samples with a FIBTEM A5 ≤12 mm, 118 had Clauss fibrinogen >2 g/L, resulting in false positive selection of 81% of women. Using FIBTEM A5 ≤ 15 mm: 97% (30/31) of the samples with Clauss fibrinogen ≤2 g/L were accurately selected; yet 89% (248/278) of samples that were selected had a fibrinogen concentration of >2 g/L. Based on the Youden index, the optimal cut-off point in our cohort was a FIBTEM A5 of 12mm with sensitivity 87% and specificity 81%. CONCLUSIONS Our findings suggest that if FIBTEM A5 lower than 12 mm would have been used to detect women with fibrinogen concentrations below 2 g/L in order to treat them with fibrinogen concentrate, 87 % of the women with fibrinogen below 2 g/L would correctly have received fibrinogen. However, most women (81%) receiving fibrinogen concentrate would not have needed it, because they had plasma fibrinogen concentrations above 2 g/L.