Fibrin degradation products (FDP) are substances that remain in your bloodstream after your body dissolves a blood clot. Your fibrinolytic (clot-busting) system manages and regulates clot dissolving.
When you cut yourself, the injured blood vessel constricts to stop bleeding and promote healing. This process is called hemostasis. Platelets in your blood gather together and stick to the injury site to form a plug or clot. The formation of the plug or clot is called the clotting cascade.
Fibrin is a protein that aids in clotting. Clotting, also called coagulation, at the wound site produces a mass of fibrin threads called a net. The net remains in place until the cut is healed. As the cut heals, the clotting slows down. Eventually the clot breaks down and dissolves.
When the clot and fibrin net dissolve, fragments of protein are released into the body. These fragments are fibrin degradation products (FDPs). If your body is unable to dissolve a clot, you may have abnormal levels of FDPs.
Blood tests can measure your level of FDPs to see if you have a clotting disorder. The fibrin degradation products test is a specific test that determines the amount of FDPs in your blood. The test is also known as the fibrin split products (FSPs) test, or the fibrin breakdown products test.
The fibrin degradation products test may be ordered to help determine if you have the following health conditions:
- deep vein thrombosis, a blood clot in a deep vein
- pulmonary embolism, a blockage in the main artery of the lung
- kidney disease
The test may also be ordered if you have other clotting disorders, or if your doctor believes you have disseminated intravascular coagulation (DIC).
Symptoms of DIC include:
- bleeding gums
- severe muscle pain
- severe abdominal pain
- reduced urine output
The fibrin degradation products test may also be used if you’re receiving treatment for a clotting disorder. Your doctor will compare test results to determine if treatment is effective for controlling your symptoms.
A nurse or lab technician typically administers the fibrin degradation products test. You’ll need to provide a blood sample.
A nurse or lab technician will draw blood from your arm using a needle. They’ll collect the blood in a tube and send it to a lab for analysis. Your doctor will provide you with your results and information on what they mean.
You may experience some discomfort when the blood sample is drawn. Needle sticks may result in pain at the injection site during the test. Following the test, you may experience pain or throbbing at the injection site.
In general, the risks of the fibrin degradation products test are minimal. These risks are common for most routine blood tests and include:
- difficulty obtaining a sample, resulting in multiple needle sticks
- excessive bleeding at the needle site
- fainting as a result of blood loss
- the accumulation of blood under the skin, known as a hematoma
- development of infection where the skin is broken by the needle
Certain drugs may increase the level of FDPs in your bloodstream. Examples include:
- barbiturates (a type of sedative)
- heparin (used to treat blood clots)
- streptokinase (used to dissolve blood clots)
- urokinase (used to dissolve blood clots)
If you use any of these medications, your doctor may tell you to stop taking them before the test. However, do not stop taking any medications without talking to your doctor.
Normal results for the fibrin degradation products test are less than 10 mcg/mL (micrograms per milliliter). However, your results will depend on the laboratory completing the analysis of your sample. Talk with your doctor about your results and what they mean. FDP levels that are higher than normal may indicate a clotting disorder.
A number of different health problems can cause a clotting disorder, including:
- abruption placentae (when the placenta prematurely separates from the wall of the uterus before the baby is born)
- congenital heart disease
- hypoxia (when the body doesn’t get enough oxygen)
- intrauterine fetal death (when the baby dies in the womb)
- liver disease (cirrhosis)
- renal disease (kidney disease)
- septicemia (bacterial infection in the blood)
- preeclampsia (high blood pressure during pregnancy)
- thromboembolic states (when abnormal blood clots form)
- transplant rejection (when the body’s immune system attacks an organ after a transplant)
If your fibrin degradation products level is elevated, you’ll need to undergo additional testing to determine what’s causing your condition.