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Introduction ⬇

When fibrin is split by plasmin, positive tests for fibrin degradation (split) products, identified by the letters X, Y, D, and E, are produced. These products have an anticoagulant action and inhibit clotting when they are present in excess in the circulation. Increased levels of FDPs may occur with a variety of pathologic processes in which clot formation and lysis occur.

This test is done to establish the diagnosis of DIC and other thromboembolic disorders.

Normal Findings ⬆ ⬇

Negative at 1:4 dilution or <10 μg/mL (<10 mg/L)

Clinical Alert

Patients with very high levels of FDPs have blood that does not clot or clots poorly.Critical Value>40 g/mL (>40 mg/L)

Procedure ⬆ ⬇

  1. Place a venous blood sample of at least 4.5 mL in a tube containing thrombin and an inhibitor of fibrinolysis (reptilase, aprotinin, and calcium). Label the specimen with the patient’s name, date and time of collection, and test(s) ordered. Place the specimen in a biohazard bag.

  2. The blood should be completely clotted before the test is started because the end products (X, Y, D, and E) are due to degradation of fibrinogen and fibrin.

Clinical Implications ⬆ ⬇

Increased FDPs are associated with DIC and are seen in:

  1. Primary fibrinolysis

  2. Venous thrombosis

  3. Thoracic and cardiac surgery or kidney transplantation

  4. Acute MI

  5. Pulmonary embolism

  6. Carcinoma

  7. Liver disease

Interventions ⬆ ⬇

Pretest Patient Care

  1. Explain test purpose and procedure.

  2. Follow guidelines in Chapter 1 for safe, effective, informed pretest care.

Posttest Patient Care

  1. Review test results; report and record findings. Modify the nursing care plan as needed. Counsel the patient regarding abnormal findings; explain the need for possible follow-up testing and treatment. Monitor for DIC and thrombosis.

  2. Follow guidelines in Chapter 1 for safe, effective, informed posttest care.

Interfering Factors ⬆

  1. Because all of the laboratory methods are sensitive to fibrinogen as well as FDPs, it is essential that no unclotted fibrinogen be left in the serum preparation. False-positive reactions can result if any fibrinogen is present.

  2. False-positive results occur with heparin therapy.

  3. The presence of rheumatoid factor (RA) may cause falsely high FSP and FDP values.

  4. see Appendix E for drugs that affect test outcomes.