No, I am in the UK, which is where it was developed in the early 1980’s.  A lot of Countries have taken it up though, but I am not sure about the USA.  I do not believe it is particularly expensive to analyse the blood spots and am sure your Endocrinologist will be aware of the procedure but whether he will be prepared to adopt it, will probably depend on whether he has access to a lab that is appropriately equiped to deal with analysing the blood spots.