Yes, I have it in my Lab Test Ref. book. Here's what it says:
Antithrombin III (AT-III, Heparin Cofactor, Serine Protease inhibitor, etc.)-- "This test is used to evaluate patients suspected of having hypercoagulable states. It is also used to help identify the cause of 'heparin resistance' in patients receiving heparin therapy. AT-III is an alpha2 globulin produced in the liver. It inhibits the serum proteases involved in coagulation..." etc.

It says abnormal findings:

Increased levels-- kidney transplant, acute hepatitis, obstructive jaundice, Vitamin K deficiency

Decreased levels-- disseminated intravascular coagulation, hypercoag. states (e.g. DVT), hepatic disorders (esp. cirrhosis), nephrotic syndrome, protein-wasting diseases (malignancy) hereditary familial deficiency of AT-III.

Don't let the scarey stuff alarm you. Those are in there, but seem to be quite rare (like the transplant, malignancy, etc.)

I know what it's like to not be able to find something you are trying to research. Hope this helps. Take care!

Keep Smiling!
Geri