Fibrinogen measurement in cardiac surgery with cardiopulmonary bypass: Analysis of repeatability and agreement of Clauss method within and between six different laboratories

Abstract

SummaryPlasma fibrinogen concentration is important for coagulopathy assessment, and is most commonly measured using the Clauss method. Several factors, including device type and reagent, have been shown to affect results. The study objective was to evaluate performance and repeatability of the Clauss method and to assess differences between measurements performed during and after cardiopulmonary bypass (CPB), by testing plasma samples from patients undergoing cardiac surgery with CPB. Samples were collected from 30 patients before surgery, approximately 20 minutes before weaning from CPB, and 5 minutes after CPB and protamine. Fibrinogen concentration was determined using the Clauss method at six quality-controlled specialised laboratories, according to accredited standard operating procedures. Regarding within-centre agreement for Clauss measurement, mean differences between duplicate measurements were between 0.00 g/l and 0.15 g/l, with intervals for 95% limits of agreement for mean Bland-Altman differences up to 1.3 g/l. Regarding between-centre agreement, some mean differences between pairs of centres were above 0.5 g/l. Differences of up to ~2 g/l were observed with individual samples. Increased variability was observed between centres, with inter-class correlation values below 0.5 suggesting only fair agreement. There were no significant differences in fibrinogen concentration before weaning from CPB and after CPB for most centres and methods. In conclusion, considerable differences exist between Clauss-based plasma fibrinogen measured using different detection methods. Nevertheless, the similarity between measurements shortly before weaning from CPB and after CPB within centres suggests that on-pump measurements could provide an early estimation of fibrinogen deficit after CPB and thus guidance for haemostatic therapy.

Thromboelastography and Thromboelastometry in Assessment of Fibrinogen Deficiency and Prediction for Transfusion Requirement: A Descriptive Review

“…The former was ascribed to an unexplained interference with the optical source by hydroxyethyl starch and the latter was due to impairment of fibrin polymerization induced by the fluid. In addition, the fibrinogen measurement by the Clauss method for the same set of plasma samples can vary within and between laboratories [94].…”

Clinical Utility of the Ratio Between Circulating Fibrinogen and Fibrin (ogen) Degradation Products for Evaluating Coronary Artery Disease in Type 2 Diabetic Patients

“…All samples were immediately refrigerated and transported to the Department of Clinical Laboratory for determining lipid profiles, FBG, glycosylated hemoglobin A1c (HbA1c), high-sensitive C-reactive protein (hs-CRP), blood urea nitrogen (BUN), creatinine, uric acid and a spectrum of hematological and liver functional tests by standard laboratory techniques on a Hitachi 912 Analyzer (Roche Diagnostics, Germany). Serum Fg level was determined using the Clauss method as previously reported,[ 19 ] and FDP level (including D and E fragments, D-dimer, and additional intermediate cleavage products) was assessed by a sandwich immunoassay. The Fg/FDP ratio was then calculated.…”

Development and validation of an app-based cell counter for use in the clinical laboratory setting

“…are familiar to pathologists and laboratorians alike, the approach to demonstrating similarity between data sets is often less well-defined. Some studies rely exclusively on the correlation coefficient to establish statistical similarity; however,[ 12 13 14 15 16 17 ] the combination of the correlation coefficient with Bland–Altman analysis is a more stringent approach to demonstrating functional equivalence between a novel and an established method and is subject to fewer sources of error. [ 9 10 12 13 16 ] The superiority of a combined approach is evidenced by our results for peripheral blood basophils: Although only moderate correlation was observed for this cell category ( r = 0.684; Figure 2f , upper panel), the accompanying Bland–Altman analysis [ Figure 2f , lower panel] demonstrated that this lack of correlation does not represent a systematic discrepancy between the two methods.…”