Your doctor in Scotland will likely be ordering 3 months of meds for you when you come here. Hopefully you will be on a stable dose not still be trying to find the right dose. Once you are stable testing can be done monthly which will require you to have two tests here if you have one shortly before leaving Scotland and one upon returning. One question is does your insurance cover you when in the US? Clinical labs have ridiculous starting charges for their labs. Insurance companies here have negotiated discounts from the list cost which are often over a 90% reduction. You don't want to pay their list price. If you have no coverage you may wish to contact the labs in the area to negotiate your discount, paying cash at the time of service.
Labcorp has a program,( I don't know what the discount might be) called Lab access partnership program but here is the Oct 2012 price list
http://www.liviahealth.com/wp-conten...-2012-copy.pdf
Quest does not seem to have any discount program unless you qualify under HHS Federal Poverty guidelines, but you can always ask. Other labs may also have programs. The other concern is if a dose alteration is needed, are you going to have someone local who can provide you with care? Plan ahead.