What are the medical guidelines for a dot medical card?

I used to work for an occupational med office which signed off on them all the time... I don't remember exactly. However, i know that a physical is required, but I believe its pretty basic. I remember specifically blood pressure must be 140/90 or below, i think there was a hearing test, and usually a drug screen is included. This was at least 7 years ago, so regulations may have changed.