Plasma plasminogen testing is used to assess plasminogen levels in a plasma sample. During fibrinolysis, plasmin dissolves fibrin clots to prevent excessive coagulation and impaired blood flow. Plasmin doesn't circulate in active form, however, so it can't be directly measured. Its circulating precursor, plasminogen, can be measured and used to evaluate the fibrinolytic system.
- To assess fibrinolysis
- To detect congenital and acquired fibrinolytic disorders
- Explain to the patient that this test is used to evaluate blood clotting.
- Tell him that a blood sample will be taken. Explain who will perform the venipuncture and when.
- Reassure him that drawing a blood sample will take less than 3 minutes.
- Explain that he may feel slight discomfort from the tourniquet pressure and the needle puncture.
- Check patient history for use of thrombolytic drugs, such as streptokinase or urokinase, and oral contraceptives, which may cause inaccurate test results. If these drugs must be continued, note this on the laboratory slip.
- Inform the patient that food or fluids need not be restricted before the test.
Procedure and posttest cane
- Perform a venipuncture and collect the sample in a 7-ml blue-top tube.
- If a hematoma develops at the venipuncture site, apply warm soaks.
- Resume medications withheld before the test.
- Collect the sample as quickly as possible to prevent stasis, which can slow blood flow, causing coagulation and plasminogen activation.
- To prevent hemolysis, avoid excessive probing during venipuncture and rough handling of the sample.
- Immediately after collection, invert the tube gently several times and send the sample to the laboratory. If testing must be delayed, plasma must be separated and frozen at -94°F (-70°C).
Normal plasminogen activity is 80% to 123 mg/dl. Plasminogen activity: 80% to 123%.
Diminished plasminogen levels can result from disseminated intravascular coagulation, tumors, preeclampsia, and eclampsia, which accelerate plasminogen conversion to plasmin and increase fibrinolysis. Some liver diseases prevent formation of sufficient plasminogen, decreasing fibrinolysis
- Failure to use the proper collection tube, to adequately mix the sample and the citrate, to send the sample to the laboratory immediately, or to have the sample separated and frozen.
- Hemolysis due to excessive probing during venipuncture or to rough handling of the sample.
- Hemoconcentration due to prolonged tourniquet use before venipuncture (possible false-low).
- Oral contraceptives (possible slight increase).
- Thrombolytic drugs, such as streptokl nase and urokinase (possible decrease).
- Transfusion of whole blood, plasma, or fractions within 4 weeks of the test.