Fibrin degradation products (FDP) are substances that remain in your bloodstream after your body dissolves a blood clot. Clot dissolving is managed and regulated by your fibrinolytic system.
When you cut yourself, the injured blood vessel constricts to stop bleeding and promote healing. This process is called hemostatis. 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.
Clotting, also called coagulation, at the wound site produces a mass of fibrin threads called a net that remains in place until the cut is healed. Fibrin is a protein that aids in clotting. 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 or FDPs. If your body is unable to dissolve a clot, you may have abnormal levels of FDPs.
Blood tests can be used to measure your level of FDPs to see if you have a clotting disorder. One specific test that determines the amount of FDPs in your blood is the fibrin degradation products test. 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 (DVT), a blood clot in a deep vein
- pulmonary embolism (PE), a blockage in the main artery of the lung
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 of the gums
- severe muscle pain
- severe abdominal pain
- a reduction in urine output
The fibrin degradation products test may also be used if you are 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 in a clinical setting typically administers the fibrin degradation products test. You will be required to provide a blood sample. The blood sample is commonly extracted through the arm by a needle. The blood will be collected in a tube and sent to a lab for analysis. Once the results are reported from the lab, your doctor will be able to provide you with more information about the results and 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 to most blood tests that are routinely performed. Potential risks for the test 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: type of sedative
- heparin: to treat blood clots
- streptokinase: to dissolve blood clots
- urokinase: to dissolve blood clots
If you use any of these medications, your doctor may tell you to stop taking them before the test. Do not stop taking any medications without first talking to your doctor.
Your results will depend on the laboratory completing the analysis of your sample. Talk with your doctor about your results and what they mean. Normal results for the fibrin degradation products test are less than 10 mcg/mL (micrograms per milliliter). If you have higher-than-normal FDP levels, this may indicate the presence of a clotting disorder.
A clotting disorder can be caused by a number of different health problems, 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 will need to undergo additional testing to determine what is causing your condition.