Test Catalog

Test ID: FIBTP    
Fibrinogen, Plasma

Useful For Suggests clinical disorders or settings where the test may be helpful

Detecting increased or decreased fibrinogen (factor I) concentration of acquired or congenital origin


Monitoring severity and treatment of disseminated intravascular coagulation and fibrinolysis

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Fibrinogen, also known as factor I, is a plasma protein that can be transformed by thrombin into a fibrin gel ("the clot"). Fibrinogen is synthesized in the liver and circulates in the plasma as a disulfide-bonded dimer of 3 subunit chains. The biological half-life of plasma fibrinogen is 3 to 5 days.


An isolated deficiency of fibrinogen may be inherited as an autosomal recessive trait (afibrinogenemia or hypofibrinogenemia) and is one of the rarest of the inherited coagulation factor deficiencies.


Acquired causes of decreased fibrinogen levels include acute or decompensated intravascular coagulation and fibrinolysis (disseminated intravascular coagulation: DIC), advanced liver disease, L-asparaginase therapy, and therapy with fibrinolytic agents (eg, streptokinase, urokinase, tissue plasminogen activator).


Fibrinogen function abnormalities, dysfibrinogenemias, may be inherited (congenital) or acquired. Patients with dysfibrinogenemia are generally asymptomatic. However, the congenital dysfibrinogenemias are more likely to be associated with bleeding or thrombotic disorders than the acquired dysfibrinogenemias are. While the dysfibrinogenemias are generally not associated with clinically significant hemostasis problems, they characteristically produce a prolonged thrombin time clotting test.


Acquired dysfibrinogenemias mainly occur in association with liver disease (eg, chronic hepatitis, hepatoma) or kidney diseases (eg, chronic glomerulonephritis, hypernephroma) and usually are associated with elevated fibrinogen levels.


Fibrinogen is an acute phase reactant, so a number of acquired conditions can result in an increase in its plasma concentration:

-Acute or chronic inflammatory illnesses

-Nephrotic syndrome

-Liver disease and cirrhosis

-Pregnancy or estrogen therapy

-Compensated intravascular coagulation




The finding of an increased level of fibrinogen in a patient with obscure symptoms suggests an organic rather than a functional condition. Chronically increased fibrinogen has been recognized as a risk factor for development of arterial thromboembolism.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

200-393 mg/dL

Interpretation Provides information to assist in interpretation of the test results

Fibrinogen may be decreased in acquired conditions such as liver disease and acute intravascular coagulation and fibrinolysis and disseminated intravascular coagulation (ICF/DIC).


Fibrinogen may be decreased in rare conditions including congenital afibrinogenemia or hypofibrinogenemia.


Fibrinogen may be elevated with acute or chronic inflammatory conditions.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

In patients with dysfibrinogenemias, fibrinogen concentration is often low and may be further differentiated from hypofibrinogenemia by measuring the fibrinogen antigen concentration.


Direct oral anticoagulants and high-concentrations of heparin (>2 U/mL) can falsely decrease fibrinogen concentration

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Mackie IJ, Kitchen S, Machin SJ, Lowe GD: Haemostais and Thrombosis Task Force of the British Committee for standards in Haematology. Guidelines for fibrinogen assays. Br J Haemotol. 2003;121:396-304

2. Boender J, Kruip MJ, Leebeek FW.: A diagnostic approach to mild bleeding disorders. J Thromb Haemost. 2016;14:1507-1516

Special Instructions Library of PDFs including pertinent information and forms related to the test