Laboratory testing for fibrinogen abnormalities

Abstract

Fibrinogen is essential for the formation of a fibrin clot. Acquired and congenital disorders of fibrinogen may result in decreased concentration or altered function of fibrinogen, often leading to an increased risk of bleeding. Routine coagulation testing and specialized laboratory investigations can guide diagnosis in patients suspected of having a fibrinogen abnormality. This article summarizes the types of laboratory assays that are used to assess fibrinogen disorders, and key abnormalities found in different types of fibrinogen disorders. Am. J. Hematol. 83:928-931, 2008. V

Identification and characterization of novel mutations implicated in congenital fibrinogen disorders

“…Normal fibrinogen levels in these individuals could be attributed to the low sensitivity of the antigen and function assays as these subjects had normal or only slightly prolonged times for the more sensitive, TT and RT assays. This might suggest that these assays are not always efficient measures of laboratory deficiencies 18. Interestingly, of the clinically asymptomatic subjects with fibrinogen mutations, 50% and 70% had prolonged TT and RT, respectively with an average TT of 29.89 seconds and RT of 27.58 seconds (normal range 15‐19 seconds).…”

Assessment of Selected ROTEM Parameters, Kinetics of Fibrinogen Polymerization and Plasmin Amidolytic Activity in Patients with Congenital Fibrinogen Defects

“…In these 3 cases, the ratio between functional activity to antigen amounted to 0.44 and 0.54 and 0.46 respectively. Previous studies including Krammer et al [26] indicate that the ratio lower than 0.7 allows the vast majority of the dysFI patients to be to identified [6][7][8]27]. CT -coagulation time; CFT -clot formation time; α -angle; MCF -maximum clot firmness; ML -maximum lysis in the cohort of patients with hypo-and dysfibrinogenemia…”

Evaluating for Suspected Child Abuse: Conditions That Predispose to Bleeding

“…Clinical presentations range from mild to severe bleeding, and some patients have an increased risk of thrombosis as well, depending on the causative mutation. 86,87 Fibrinogen deficiencies can also be acquired in other medical disorders, such as liver disease or consumptive coagulopathy. 87 Severe disorders of fibrinogen result in prolongation of PT and aPTT, but milder disorders might be missed by these screening tests.…”

“…86,87 Fibrinogen deficiencies can also be acquired in other medical disorders, such as liver disease or consumptive coagulopathy. 87 Severe disorders of fibrinogen result in prolongation of PT and aPTT, but milder disorders might be missed by these screening tests. Thrombin time tests conversion of fibrinogen to fibrin and is more sensitive to both deficiencies and abnormalities of fibrinogen than are PT and aPTT.…”

“…One can also measure the amount of fibrinogen antigen through a variety of methods. 87 Most patients with dysfibrinogenemia are asymptomatic. Bleeding, when it is present, is typically mild and triggered by surgery or trauma, and thrombosis can occur.…”