Last year Medicare did a "pre-edit audit" on all chiropractic claims. In the audit, all notes were requested for any chiropractic visits, 98940, 98941, 98942. As a result of that audit Medicare determined that the 98941 code was mis-used over 85% of the time. So, now they are requesting medical documentation on all 98941's and some 98940's. There are many dc's that do the entire spine every time a patient comes in. Under Medicare guidelines, they only pay for manipulation of the spine if it is due to an acute situation. They consider any thing else maintenance which is not covered. Even if the dr feels that the patient needs it and it helps the pt, etc etc, it is not a covered Medicare expense. (Please don't take my answer the wrong way, I believe that many Medicare patients are kept active and functioning due to chiropractic treatments.)
I cannot tell you specifically what needs to be included in the patient's notes but I can say that generally they are looking in the notes to see how many regions are documented as being treated AND if that documentation shows an acute situation. They are looking to see if the documentation indicates that it was maintenance treatment or acute flare up, etc. And the info that DMK gave is also true, dx's must be valid and AT modifier to indicate acute.
What I have often seen is a DC using a 98941 (3-4 regions) but only indicating 1-2 regions in their dx's. For example, 98941 w/dx's 739.3 & 722.52. Only one region indicated in dx's but 3-4 treated??