Fibrin Degradation Product Assay (FDP Assay)

Overview

The Fibrin Degradation Product Assay (FDP Assay) is a diagnostic test used to measure the levels of fibrin degradation products (FDPs) in the blood. FDPs, also called fibrin split products, are fragments formed when fibrin clots are broken down by plasmin during the body’s natural clot dissolution process. Under normal conditions, clots form to stop bleeding and are dissolved once healing occurs. However, in certain diseases and clotting disorders, FDP levels become abnormally elevated, indicating ongoing clot breakdown. FDP testing plays an important role in evaluating bleeding disorders, clotting abnormalities, malignancies, thrombotic therapy monitoring, and conditions such as disseminated intravascular coagulation (DIC), pulmonary embolism, and deep vein thrombosis (DVT). Subtypes of FDP include D-dimer, Fragment D, and Fragment E, each reflecting different stages of fibrin breakdown.

Symptoms

(Clinical features indicating the need for FDP testing)

1. Prolonged or unexplained bleeding after injury or surgery.
2. Recurrent blood clots, such as in DVT or pulmonary embolism.
3. Shortness of breath, chest pain, or leg swelling, suggestive of clot-related conditions.
4. Unexplained bruising or hematomas.
5. Neurological signs such as sudden weakness, facial droop, or difficulty speaking in cases of stroke.
6. Persistent fever and weakness in cancer patients.
7. Systemic signs of DIC, such as widespread bleeding, organ dysfunction, and clotting complications.

Causes

(Underlying conditions leading to abnormal FDP levels)

1. Clotting and bleeding disorders such as disseminated intravascular coagulation (DIC).
2. Thrombotic conditions: pulmonary embolism, deep vein thrombosis, myocardial infarction, and stroke.
3. Malignancies: colorectal cancer and other tumors (lung, breast, stomach, ovary, liver, colon, cervix, pancreas, thyroid, esophagus, lymphoma, and trophoblastic tumors).
4. Leukemia and hematological disorders.
5. Severe trauma or burns leading to systemic clotting abnormalities.
6. Kidney disease associated with altered clotting profiles.
7. Thrombotic therapy monitoring, especially during anticoagulant treatments.
8. Dysfibrinogenemia and fibrinogenolysis, primary or secondary, leading to abnormal fibrin breakdown.

Risk factors

(Populations more likely to show abnormal FDP levels)

1. Patients with cancer, especially colorectal, lung, breast, and ovarian malignancies.
2. Individuals with a history of blood clots, such as DVT or pulmonary embolism.
3. Patients on thrombotic therapy, where FDP monitoring helps assess treatment effectiveness.
4. Individuals with cardiovascular conditions, including myocardial infarction and stroke.
5. Patients with systemic infections or sepsis, prone to developing DIC.
6. Burn and trauma victims, who are at risk of clotting abnormalities.
7. Individuals with kidney disease or liver dysfunction, which impact clotting factor metabolism.
8. Pregnant women or post-surgical patients, with increased risk of thromboembolic complications.

Prevention

(Strategies to ensure accurate FDP testing and reduce risks of clotting disorders)

1. Accurate sample collection:
   1. Collect blood using citrate or oxalate additive tubes (light blue top).
   2. Maintain the correct anticoagulant-to-blood ratio (1 part anticoagulant to 9 parts blood).
   3. Avoid over- or under-filling tubes.
2. Reliable laboratory methods: FDP detection involves mixing patient plasma with latex particles coated with monoclonal anti-FDP antibodies. Agglutination indicates FDP presence.
3. Clinical monitoring:
   1. Regular FDP testing in high-risk patients (those with DIC, cancer, or thrombotic conditions).
   2. Use FDP levels along with D-dimer and other coagulation markers for accurate diagnosis.
4. Prevent thrombotic complications: timely diagnosis and management of DVT, pulmonary embolism, and myocardial infarction reduce morbidity.
5. Cancer monitoring: FDP can serve as a tumor marker (Onko-Sure test), particularly useful for colorectal cancer, and in other malignancies for tracking treatment response.
6. Education and awareness: patients should be informed about signs of clotting or bleeding (unexplained swelling, chest pain, or persistent bleeding) and seek medical care promptly.
7. Integration with clinical history: FDP results should always be interpreted alongside symptoms, risk factors, and related tests for accurate management.