Fibrinogen

Specimen Required

Sodium Citrate (PT Vial)

Fasting Required

Purpose of the Test

To determine whether your fibrinogen level is adequate to allow normal blood clotting, to help diagnose disseminated intravascular coagulation (DIC), to help determine whether you have an inherited fibrinogen deficiency or abnormality. Sometimes as a non-specific marker of inflammation in the blood. Very occasionally to help evaluate your risk of developing cardiovascular disease

When this test is required

The doctor may request a fibrinogen test when a patient has unexplained or prolonged bleeding and/or an abnormal PT and aPTT test result. The test can also be used when patients have symptoms of Disseminated Intravascular Coagulation DIC, such as: bleeding gums, nausea, vomiting, severe muscle and abdominal pain, seizures and oliguria (decreased urine output), or when the doctor is monitoring treatment for DIC.Fibrinogen testing can also be performed with other coagulation factor tests when there is suspicion that the patient may have an inherited factor deficiency or dysfunction, or when the doctor wants to evaluate and monitor over a period of time the clotting ability of a patient with an acquired bleeding disorder, particularly in liver disease.In some cases, fibrinogen testing is performed with other tests when the doctor wants to evaluate a patient’s risk of developing cardiovascular disease.

What the Test Detects

Fibrinogen is a coagulation factor, a protein that is essential for blood clot formation. It is produced by the liver and released into the circulation as needed along with over 20 other clotting factors. Normally, when a body tissue or blood vessel wall is injured a process called the coagulation cascade activates these factors. As the cascade nears completion, soluble fibrinogen (fibrinogen dissolved in fluid) is changed into insoluble fibrin threads. These threads cross-link to form a fibrin net and then stabilise at the injury site. The net adheres there, along with aggregated cell fragments called platelets, to form a stable blood clot. This barrier prevents additional blood loss and remains in place until the area has healed.How is the sample collected for testing?A blood sample is collected by inserting a needle into a vein in the arm. As an alternative, particularly in paediatric care, the blood sample is collected by quickly pricking the fingertip with a lancet.Is any test preparation needed to ensure the quality of the sample?No test preparation is needed.

Preparation for the Test

None

Sample Requirements

A blood sample taken from a vein in your arm, or sometimes, via a finger prick (mainly performed in children)

Additional Notes

Blood transfusions within the past month may affect fibrinogen test results. Certain drugs may cause decreased levels, including: anabolic steroids, androgens, Phenobarbital, Fibrinolytic drugs (streptokinase, urokinase, tPA) and sodium valproate. Moderate elevations in fibrinogen may be seen sometimes with pregnancy, cigarette smoking, and with oral contraceptives, HRT or oestrogen use.Dysfibrinogenemia, is a rare coagulation disorder caused by a mutation in the gene controlling the production of fibrinogen in the liver. It causes the liver to make an abnormal fibrinogen, one that resists degradation when converted to fibrin. Dysfibrinogenaemia is associated predominantly with venous thrombosis (inappropriate blood clot formation in the veins). PT, aPTT, and Thrombin Time are used to screen for this condition which is then confirmed with additional specialised blood tests. Patients with fibrinogen deficiency or dysfibrinogenaemia may experience poor wound healing.

Selected Tests