Plasminogen activator inhibitors (synonyms: plasminogen activator inhibitors, PAIs) are the proteins in the blood that are involved in blood clotting. They act as inhibitors of fibrinolysis (fibrin cleavage; the body’s own dissolution of a blood clot). There are four types of plasminogen activator inhibitors, with type 1 being the most important.
Plasminogen activator inhibitor type 1 (PAI-1) is the most important inhibitor of tissue plasminogen activator (t-PA) and urokinase, both of which convert inactive plasminogen to plasmin. The task of plasmin is to break down the fibrin polymers, which are clotting products that stop bleeding, into fibrin and fibrinogen. In this way, they directly inhibit fibrinolysis, i.e. the dissolution of blood clots in the body. For this reason, a tendency to thrombosis is present when PAI is elevated.
The procedure
Material needed
- Citrate plasma (no mailing/driving service).
- EDTA whole blood (gene analysis)
Preparation of the patient
- Not necessary
Disruptive factors
- Fill monovette completely, mix immediately to avoid coagulation
Normal value
| Investigation | Norm |
| PAI- determination (citrate blood) | <10 U/ml |
| Gene analysis (EDTA blood) | Negative |
Indications
- Suspected congenital/acquired tendency to thrombosis (thrombophilia).
Interpretation
Interpretation of increased values
- Thrombophilia (tendency to thrombosis); typical high-risk patients are those with: Smokers, obesity; metabolic syndrome, hypertriglyceridemia, oral contraceptives (ovulation inhibitor use).
Interpretation of lowered values
- It is possible that a decreased PAI value is associated with a bleeding tendency