What is Antithrombin III?
Antithrombin III is a protein that helps control blood coagulation. The protein stops certain enzymes from working, thus allowing blood to flow properly. Low levels of the protein can be associated with clotting disorders, liver cirrhosis and possibly an inherited disorder known as Antithrombin Deficiency. Drugs like heparin exponentially increase antithrombin levels in the blood to stop coagulation – thus thinning the blood. A high antithrombin level is not associated with bleeding disorders, but it could be an indication of anabolic steroid use.

Normal Value Range

  • Negative Pregnancy Adult: 70 to 130 percent
  • Pregnancy Trimester One: 89 to 114 percent
  • Pregnancy Trimester Two: 88 to 112 percent
  • Pregnancy Trimester Three: 82 to 116 percent

< Laboratory Values During Pregnancy