Medical exam--what are they REALLY looking for?

We are in the beginning stages of applying for a visa but as a freakshow worrier I am already thinking about the medical exam for my husband.  Or rather, he is thinking about it.  Alan has a disability (spina bifida) and we're worried that they might not deem him "healthy."  Is there anyone who's been through it who can tell me what they're looking for? My impression is that it's mainly communicable diseases, but...you never know...

We just went through the process and as a matter of fact, had our interview this morning. My DH is a Type II diabetic, and I was concerned as well. They are basically only looking for communicable diseases (STD/AIDS and TB). They classified him as a Class B ('A' being healthy and so on)

I do know a friend who is having to apply for a medical waiver- original application was denied but her DH is a paraplegic and beginning stages of MS and Type II. They seem confident that the waiver will be approved.

Shouldn't be much hassle, but as a warning, if they do require a medical waiver, there will be an additional cost. Not sure how much tho.

Thanks for the info...Is the medical waiver provided by the embassy or is it something we have to get through our doctor?  Would it be worth it to speak to the embassy before the medical or just wait?