Functional fibrinogen: what it is and what you should know

For those fasting the principles of physiology and biochemistry, first to explainwhat is fibrinogen, I will make a brief introduction to what is the composition of our blood.

Ablood clotit is an aggregate of cellular fragments calledplatelets. Theseplateletsare held together by different fibers, the main one being thefibrin. Fibrin comes from thefibrinogen. Afteralbuminsand theglobine, thefibrinogenis generally the third datum ofblood protein (plasma) more abundant.

How to read blood tests focusing on fibrinogen. Reference values.

Fibrinogen: what it is

Thefibrinogenit is a plasma protein produced by the liver for the purpose of promoting blood clotting (haemostasis).

The other words, thefibrinogenit is a factor of fundamental importance for blood coagulation and platelet activity. Thefibrinogenconverts tofibrinand allows platelets to perform their duty, for example, ofheal wounds and stop bleeding.

Functional fibrinogen: what it is

In the laboratory context, the texts to detect ifibrinogen valuesthey are different, one of which is called "Functional Fibrinogen".

In general, the examination of thefunctional fibrinogenis required when investigating infections, thrombosis, coagulation errors, bleeding, bleeding risks, easy bruising ... Often, the fibrinogen values ​​are investigated together with thethrombin time(TT).

We talk aboutfunctionally fibrinogenbecause the laboratory method used for the assay is called the "functional method". At the level of our organism, the term "functional fibrinogen”Has no relevance. He only has it in the laboratory setting.

In the laboratory, different techniques are used to estimate the values ​​offibrinogen. A reagent is often used to measure the contribution offunctional fibrinogenthe "strength of the clot" (therefore in relation to the platelets, fibrinogen content in proportion to the platelet content).

Based on the doctor's requests and ongoing investigations, the patient can undergo an examination for fibrinogen or functional fibrinogen.

In both cases, theexaminationevaluate the capacity blood clotting. The test may be requested as an aid in the diagnosis of various diseases, it is generally associated with other blood tests such as:

  • PT (prothrombin time)
  • APTT, activated partial thromboplastin time
  • Platelet and D-dimer count.

Occasionally the functional fibrinogen dosage it can be helpful in monitoring the degree of progression of some chronic diseases. Fibrinogen, as stated, is produced byliver and can be an indicator of the health of the liver. Sometimes the specialist requests this examination to monitor the response to an ongoing therapy in the case of various diseases.

Low fibrinogen

The normal level of fibrinogen in plasma ranges from 1.5 to 4.5 g / L (reference values: 150.00 - 450.00). NB: each laboratory takes its own reference standards as "reference values". Maybe if you think from your report that he has slightly higher or lower fibrinogen, your doctor might say "this is normal" with your medical history, your gender and the standards he uses!

When to worry in case oflow fibrinogen? The critical level of fibrinogen in plasma, below which bleeding episodes may occur, is approximately 0.5 - 1.0 g / L.

Taking some drugs can cause low fibrinogen decreasing its levels. We are talking about anabolic steroid drugs, androgens, streptokinase, urokinase and some antiepileptic drugs used to counter epileptic seizures or in some mental illnesses such as schizophrenia or bipolarism.

High fibrinogen

Thefibrinogenit is an "acute phase" protein. This means thatincreasesconsiderably in conditions of inflammation (any inflammation) or tissue damage (any tissue damage). It is clear that to speak only ofhigh firbinogenit does not give us much information on the possibilitiescauses.

The concentrations ofelevated fibrinogenthey are not a "specific match" forillnessesand do not provide information on thecauseor the “specific location of a disease”. In short, thehigh fibrinogenit could also be caused by a trivial onecystitisas well as from much more serious diseases and organic damage.

Thehigh fibrinogen(slightly higher) is a normal condition that is observed during thepregnancy, insmokersand in patients taking estrogen and oral contraceptives.

Normal values, high and low fibrinogen

As stated, it is not easy to talk about normal values ​​because thereference intervalsthey may differ from one laboratory to another. To understand what the normal values ​​are you should see those taken into consideration by the analysis center you contacted.

Other normal values ​​are considered:

  • Men: 200 - 375 mg / dl
  • Women: 200 - 430 mg / dl


  • Fibrinogen antigen: 149-353 mg / dl

  • Functional fibrinogen: 0.59-1.23

Also pay attention to the units of measurement used. Its normal value can also be expressed like this: 0.200 - 0.450 grams per deciliter of blood (g / dl).

For a consistent interpretation it is important to contact your doctor. Always wanting to generalize, we can say that:

If the fibrinogen is low, means that the body consumes the coagulation factors even in the absence of bleeding (so-called "disseminated intravascular coagulation"). This process is often triggered by leukemia, but if you have low fibrinogen it doesn't necessarily mean you have leukemia! That is why it is important to see this result in a much wider context.

In case of high fibrinogen there is an ongoing inflammation that the doctor must investigate.

Video: Blood Clot Formation - Coagulation Factors u0026 Platelets (May 2021).