title: Determination of plasma fibrinogen concentrations in beagle dogs, cynomolgus monkeys, New Zealand white rabbits, and Sprague-Dawley rats by using Clauss and prothrombin-time-derived assays.
abstract: The most widely used technique for determination of fibrinogen concentration is the Clauss fibrinogen (FIB(Clauss)) assay, which measures the clotting time of plasma after addition of excess thrombin. More recently, the PT-derived fibrinogen (FIB(PT)) assay has been  developed, based on the relationship between fibrinogen concentration and the kinetics of clot formation during the prothrombin time. The objective of this study was to compare the fibrinogen concentration determined by the FIB(Clauss) and FIB(PT) assays in citrated plasma samples from  healthy dogs (n = 40), monkeys (n = 40), rabbits (n = 26), and rats (n = 58) by using an automated coagulation analyzer. Results of a t test analysis indicated that the mean plasma fibrinogen concentrations measured by the 2 assays for all 4 species were  significantly different. According to Pearson correlation coefficients, the FIB(PT) assay displayed a high correlation (0.93 to 0.98) with the FIB(Clauss) assay for all species. When the FIB(PT) and FIB(Clauss) assays were compared by using Deming regression, positive or negative constant and proportional  biases emerged for all species. Intra- and interassay coefficients of variation for the FIB(PT) and FI(BClauss) assays were 0.8% to 2.3% and 1.8% to 7.4%, respectively. In conclusion, the FIB(PT) assay is a rapid and economical method for estimating fibrinogen concentration in plasma samples from  dogs, monkeys, rabbits, and rats. However, it should not be used without restriction. Further studies are required to investigate the performance of this assay in animals with various pathologic states, including coagulopathy, dysfibrinogenemia, and hypo- or hyperfibrinogenemia.
authors.affiliation: Department of Clinical Pathology, Wyeth Research, Chazy, New York, USA. mehrdad.ameri@pfizer.com
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Ameri
authors.forename: Henry A
authors.initials: HA
authors.lastname: Schnaars
authors.forename: John R
authors.initials: JR
authors.lastname: Sibley
authors.forename: David J
authors.initials: DJ
authors.lastname: Honor
mesh_terms: D000818:Animals; D001777:Blood Coagulation / Q000502:physiology*; D004285:Dogs / Q000097:blood*; D005340:Fibrinogen / Q000032:analysis*; D008252:Macaca fascicularis / Q000097:blood*; D011517:Prothrombin Time / Q000379:methods / Q000662:veterinary*; D011817:Rabbits / Q000097:blood*; D051381:Rats; D017207:Rats, Sprague-Dawley / Q000097:blood*; D012044:Regression Analysis; D013045:Species Specificity
chemical_list: D005340:Fibrinogen