I find varying information about that exam. Some sources (CertGuide, for example) say the passing score is 620 (and that's what it was when I took it myself early last year). Other sources give the number of questions as either 50 or 55. Numerous other sources do not disclose passing score information. My favorite source, CramSession.com, still lists the class as 2/5 on the easy to hard scale (to me, this indicates a lower cut score rather than a higher one is its basis for evaluation, too).
My gut feel is that 850 is a very high passing score for any MS exam and that it's unlikely that it would be that high if in fact it's been raised at all. I will keep digging and get more information to you if I can find it. Please e-mail me so I can follow up after talking to some industry friends and colleagues.
This was first published in January 2003