After a fibrin clot has formed, the fibrinolytic system acts to prevent excessive clotting. In this system, plasmin digests fibrin. Fibrinogen also may be degraded if there is a disproportion among plasmin, fibrin, and fibrinogen. The substances that result from this degradation—fibrin split products (FSP) or fibrinogen degradation products (FDP)—interfere with normal coagulation and with formation of the hemostatic platelet plug.

Normally, FSP are removed from the circulation by the liver and the reticuloendothelial system. In situations such as widespread bleeding or DIC, however, FSP are found in the serum.

Tests for FSP are performed on serum using immunologic techniques. Because FSP do not coagulate, they remain in the serum after fibrinogen is removed through clot formation. Antifibrinogen antibodies are added to the serum to detect the presence of FSP. Because normal serum contains neither FSP nor fibrinogen, there should be nothing present to react with the antibodies. If a reaction occurs, FSP are present.³⁵

• 2 to 10 mg/mL

• Heparin, fibrinolytic drugs such as streptokinase and urokinase, and large doses of barbiturates may produce elevated levels of FSP.
• Traumatic venipunctures and excessive agitation of the sample may alter test results.

• Confirmation of suspected DIC, as indicated by elevated FSP levels
• Evaluation of response to therapy with fibrinolytic drugs
• Monitoring of effects on hemostasis of trauma, extensive surgery, obstetric complications, and disorders such as liver disease

Nursing Care Before the Procedure

Client preparation is the same as that for any study involving the collection of a peripheral blood sample (see Appendix I).

• If the individual is receiving anticoagulant therapy, the time and the amount of the last dose should be noted.

A venipuncture is performed and the sample collected in a red-topped tube or in a special tube provided for the FSP test by the laboratory. As with other coagulation studies, traumatic venipunctures and excessive agitation of the sample should be avoided. The sample should be sent to the laboratory promptly.

Nursing Care After the Procedure

Care and assessment after the procedure are essentially the same as for any study involving the collection of a peripheral blood sample.

• Because the client may have a coagulation deficiency, maintain digital pressure directly on the puncture site for 3 to 5 minutes after the needle is withdrawn.
• Inspect the site for excessive bruising after the procedure.