Plasminogen Activator Inhibitor 1 

Plasminogen Activator Inhibitor 1 

No Results

No Results


Plasminogen activator inhibitor-1 (PAI-1) testing is indicated for unexplained mild-to-moderate delayed bleeding disorders, typically associated with trauma or surgery. [1]

The reference range of PAI-1 is 2-15 AU/mL. Increased PAI-1 activity is observed in elderly individuals. [2]

The normal plasma concentration is 5-40 ng/mL. [2]

Increased PAI-1 activity is observed in acute-phase reactions associated with the following: [2]




Postoperative period


Atherosclerosis and atherothrombosis


Two types of inherited PAI-1 deficiency exist, as follows: [1]

Type I: Decreased functional and immunological PAI-1 levels

Type II: Decreased functional activity despite normal protein concentration

Specimen: Citrated plasma

Collection: Blue-top tube with 3.2% sodium citrate

Centrifugation: 2000-2500 g for 15 minutes or similar method to produce platelet-poor plasma

Storage: Up to 2 hours at 2-8°C or the plasma sample should be frozen; specimen is stable for one month at -20°C or 6-9 months at -80°C

A high concentration of bilirubin might affect the PAI-1 measurement. Lipemic or hemolyzed samples should not be used.

Antifibrinolytic drugs (aminocaproic acid, tranexamic acid) could interfere with assay results and should not be used.

Plasminogen activator inhibitor-1 (PAI-1) is a glycoprotein (molecular weight, 47 kDa) that is synthesized in endothelial cells, hepatocytes, and adipocytes. It can also be released from activated platelets. PAI-1 circulates in the blood in both its active form (half-life of 30 minutes) and its latent form (half-life of 2 hours). PAI-1 is the main regulator of fibrinolytic system activation; it inhibits tissue-type plasminogen activators (tPA) and urokinase-type plasminogen activators (uPA). [1, 2]

PAI-1 testing is indicated for unexplained mild-to-moderate delayed bleeding disorders, typically associated with trauma or surgery. [1]

It is also indicated for idiopathic arterial or venous thromboembolism if other causes of thrombophilia are excluded. [3]

The PAI-1 level has a diurnal variation, peaking in the early morning. [2] Repeated measurements of PAI-1 level or antigen or other fibrinolytic markers might be useful in confirming a persistently abnormal PAI-1 level as a cause of bleeding or thrombosis. [1, 2]

Mehta R, Shapiro AD. Plasminogen activator inhibitor type 1 deficiency. Haemophilia. 2008 Nov. 14(6):1255-60. [Medline].

Vaughan DE. PAI-1 and atherothrombosis. J Thromb Haemost. 2005 Aug. 3(8):1879-83. [Medline].

Meltzer ME, Doggen CJ, de Groot PG, Rosendaal FR, Lisman T. The impact of the fibrinolytic system on the risk of venous and arterial thrombosis. Semin Thromb Hemost. 2009/07. 35(5):468-77.

Jun Teruya, MD, DSc, FCAP Professor of Pathology and Immunology, Vice Chairman for Education, Professor of Pediatrics, Professor of Medicine, Director, Tranfusion Medicine/Blood Banking Fellowship Program, Head, Division of Baylor Transfusion Medicine, Baylor College of Medicine; Director, Division of Transfusion Medicine and Coagulation, Texas Children’s Hospital

Jun Teruya, MD, DSc, FCAP is a member of the following medical societies: American Association of Blood Banks, American Society for Clinical Pathology, American Society of Hematology, College of American Pathologists, International Society on Thrombosis and Haemostasis, Massachusetts Medical Society

Disclosure: Nothing to disclose.

Vadim Kostousov, MD Research Associate, Transfusion Medicine and Coagulation, Department of Pathology and Immunology, Texas Children’s Hospital, Baylor College of Medicine

Disclosure: Nothing to disclose.

Eric B Staros, MD Associate Professor of Pathology, St Louis University School of Medicine; Director of Clinical Laboratories, Director of Cytopathology, Department of Pathology, St Louis University Hospital

Eric B Staros, MD is a member of the following medical societies: American Medical Association, American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology

Disclosure: Nothing to disclose.

Plasminogen Activator Inhibitor 1 

Research & References of Plasminogen Activator Inhibitor 1 |A&C Accounting And Tax Services