An Assay for TFPI?

Here is a message from frequent contributor “Azevlab227″:

Hi George,
Thanks so much for this valuable resource! My question is, is there a laboratory that still performs TFPI? I have had a couple of requests in recent years, but am unable to find a lab still performing the test. Thanks so much for your help!

Hello, and thank you for your question. No, I tried my favorite labs who do esoteric testing, Machaon, Esoterix, and Blood Center of Wisconsin, and none offers an assay for tissue factor pathway inhibitor (TFPI). I also tried two research kit and reagent manufacturers, Cayman Chemical and Corgenix, but no success.

Most of our readers know that TFPI is secreted by endothelial cells and inhibits both factors VIIa and Xa to control the tissue factor pathway of coagulation. There has been relatively few clinical studies devoted to TFPI, though a few implicate TFPI deficiency in thrombotic disorders. There is also no effort being devoted to developing TFPI as a therapeutic. Here is an NIH review article that provides detail on TFPI:

• Maroney SA, Mast AE. Expression of tissue factor pathway inhibitor by endothelial cells and platelets. Transfus Apher Sci 2008;38: 9–14. doi:10.1016/j.transci.2007.12.001

Added on 7-21-2010: Here is a protocol provided by Dave McGlasson, Clinical Research, Wilford Hall USAF Hospital, Lackland AFB, TX. This protocol is based upon a TFPI kit that was once available through American Diagnostica, Inc, :

• TFPI SOP from ADI