Type 2 Antithrombin Deficiency: Dr. Moll

As you can see, I’ve been stumped by Dr. Moll’s question. I’ve reviewed assay menus for my favorite hemostasis laboratories… 
…in the US and Canada, including Esoterix, Machaon, Nichols, MidwestCoag, ARUP, and Hemostasis Reference Laboratory. All offer an antithrombin (ATIII) activity and immunoassay, but none has a phenotypic assay for type IIb deficiency nor genotypic testing for any of the 12 mutations affecting the heparin binding site. I did find an excellent review, Kottke-Marchant K. Antithrombin deficiency: issues in laboratory diagnosis. Arch Pathol Lab Med 2002;126:1326-36. Meanwhile, I’ve contacted some clinical/research lab acquaintances to see if anyone assays the genotypes on a research basis. Geo.