As long as you have group coverage through an employer you should be relatively OK. Usually you have your choice of several different plans, each with different costs to the employee that will be taken out of the paycheck before you ever see it. Then based on what type of plan you have picked you will have different types of responsibilities during the year. You could choose a traditional insurance, where you are responsible for say 20% of all bills and they are responsible for 80%. Not the best if you end up with an unexpected hospitalization (Happened to me when I was diagnosed), but usually the cheapest for the employee. Then there are types of HMO's and PPO's basically you pay a co-pay when you go to the doctor, or if you need to go to the emergency room. There are rules about getting your doctor's approval before you see some specialist, but not all, depending on the plan. Your co-pays for office visits can be anything from $5 - $20 or more, I have an HMO and pay $10 an office visit, and $50 to go to the emergency room unless I am admitted in which case there is no fee. I pay nothing for any hospital stay. I pay nothing for any tests. I usually can get in to see any doctor I need to in a matter of days, sometimes the same day. The same thing with tests. It is rare that I have to wait very long for tests. I honestly don't know what we pay a year for this, but we pay for family coverage, and you would only be paying for self and spouse, so it would be different anyway. Also, ours includes a separate dental plan and eye plan that all get lumped in together.
As far as the waiting period for pre existing conditions. We have had to deal with it every time my husband has changed jobs. It has always been 30 days. After 30 on the job I have been covered in full. I worry during those 30 days. We have been able to buy COBRA but I don't know if you could do that coming from another country. Basically, you keep your insurance from where ever you had it (previous job), but pay a premium price. Its a short term thing and still really a lot better than a huge hospital bill.
Most group plans have tiers for their prescription coverage. Basically you pay one co-pay for generics, a higher co-pay for brand name, and an even higher co-pay for brand name drugs that are not common, like some of our meds. I was on Pentasa for years, but I can't remember which tier it was. I think my co-pays are $10, $20, $35. Most of my meds are $10 and of course things like prednisone that is cheaper than dirt gets charged to me at the actual price (about $3 per 100 pill). Most supplements are not automatically covered, like Iron. You could try to get a doctor to write a letter, but if it is less costly than the co-pay, it isn't worth it.
If you do decide to come to the states and you have an employer policy, maybe you can get put on it before you come and not get rid of you current one in the UK, that might avoid the whole pre-exisiting condition thing.
I hope some of this helps.
CD 20 years officially, 30 unofficially. 3 resections '93, '95 '97
Managing with strict low residue diet, keeping symptoms to a minimum. All test show small amount of ulceration, still have occasional blockages. But still have a great time with my 2 daughters and husband!
Prednisone, 6MP,Prevacid, B12 shots, Bentyl, Xifaxan.....