Hi Gemini, I don't know if I can shed any light on this for you either but I just listened to a webinar on E&M coding this morning and it did cover this somewhat. She explained that, suppose a patient comes in and has a full work up done. Then he comes in the next day ar later that week. The doc does not have to do the history again, but he must document that he has reviewed the documentation from a previous visit and he must also document, in his current chart, where the previous documentation can be found. The same goes for a doc who has seen a patient for say over 20 years. He can also document history the same way as I just explained, as long as he documents everything. The list she gave us of common codes to use interval history on were all subsequent codes (ie., sub hospital care, sub nursing care, sub domicary care, sub home care). Those codes she specifically mentioned. I don't know if there are more codes that you can use them on, though, so maybe someone else can help with that. I would also be interested if there are other codes that can use interval histories as well. Oh, and she did say that interval coding is covered in the DG's, for 95-pg 8 and for 97-pg9. Good luck