I really liked lawrence1rice's succint reply to the question posed.
It's so good I'm gonna steal it. (thanks in advance). Interqual is an evidence-based methodology of determination of medical necessity. McKesson uses these tools to determine severity of illness(how sick are they???) and intensity of service (what are we doing for them here that can't be done at another level of care
???). The problem in getting folks to meet, is that they may have only one of 2 required issues met. The key thing to remember is that medical care is a physician-driven issue. I have many times told reviewers that we disagree with their determination, and they are free to send it on up for medical review. I work trauma case management, so my people usually meet it coming in the door, but it can be a struggle for the "on the fence" type of case, or with docs who admit without medical necessity.
I take Remicaid for my RA, and developed a severe Pyelo. I had >18,000 wbc, fever >105 (Mckesson rounds up 1 degree for core body temp), hematuria and pyuria, and I'm immunocompromised, and I still didn't get admitted, cuz I could still take po (barely), wasn't vomiting, and succeeded at OP tx! I missed 10 days of work, but by God I didn't need to be in the hospital!!!:angryfire