Since you say you are new, here is some general information. Look through this link to get some info on taxonomy numbers and what purpose they serve - if you don't know about them.
http://www.adldata.com/Downloads/Glossaries/taxonomy_80.pdfPhysicians specialize in certain things. These things are defined by their taxonomy number. When doctors apply to be a participating provider in Medicare or other insurances, they must provide information as to what their specialty is (note that
specialty is different from
specialist). This information is stored in the insurance carriers' electronic files' for each participating provider, including Medicare. Should the participating provider submit a code(s) for a procedure that is outside the domain of his specialty, it will generally get rejected by the insurance carrier. For example, a family practitioner would probably not get paid for claiming to perform a colonoscopy. Neither would a naturopath get paid for claiming to perform heart surgery. Hopefully you can see the logic in this, as insurance carriers don't want to encourage doctors to practice medicine outside of the specialty there were trained in. I honestly don't know how this would be handled if the doctor was non-participating with the insurance carrier he submits the claim to - since they would not have any information on file as to his specialty.
Based on the previous paragraph, and again in general, you should compare like with like in formulating your question. Only two out of the three specialties you asked about are qualified to expect payment for a colonoscopy. Even then, it is more likely that the gastroenterologist would be the one to do a colonoscopy rather than a colorectal surgeon. But keep these two things in mind. Snipping off polyps is considered a procedure, not surgery. But that would be filed as a colonoscopy (just looking) code plus a snipping off (doing something else besides just looking) code. That is, if paid, a colonoscopy plus snipping polyps would be coded differently, and would involve more money paid to the doctor than, a colonoscopy alone.
Third - the amount a participating provider gets paid is negotiated when he applies to be a participating provider and is accepted. Theoretically, you could have five colorectal surgeons all working at the same hospital and all five could get paid a different amount for the same procedure, depending on what fee schedule they agreed to with the insurance carrier. Practically, tho, the difference in pay is likely to be minimal, if not non-existant. The country is divided up into regions by the insurance carriers, and the pay rate for a given region tends to stay the same for all participating providers, in that region, for a given insurance carrier - including Medicare. So the pay rate for a colonoscopy, for a given region, and a given insurance carrier, is likely to be close or the same for all participating providers in that region. Although there can be some differences, based on what negotiating power a given doctor has. Some of my clients are assistant professors of medicine at UCLA. As such, they get to join with the UCLA doctors in negotiating special pay rates from the insurance carriers - that are higher than for doctors in the same region who do not belong to any negotiating group.
Linda has been on the insurance carrier side of all of this and can provide more detailed information than this.