Many-- but not all-- diagnostic tests are composed of a technical and a professional component. These tests are identified in the Medicare Physician Fee Schedule. When the physician practice performs both components, the service is billed globally, with no modifier. If the technical component is performed at a hospital or facility, that is billed with modifier TC. The physician interpretation is billed with modifier 26.
A physician needs to document a "separate report" when billing for the professional component of a radiology code. Radiologists provide this type of report when interpreting an x-ray done at the hospital. It includes:
If a physician performs a test in their office, and bills for the interpretation, a similar "radiology quality" report is required in order to bill for the test. The physician needs a report on a separate piece of paper that interprets the test. It is insufficient to summarize the findings in the progress note and bill for the interpretation.
Remember that the image/tracing/report from the machine is part of the technical component. These are the results of the test. The interpretation and report is a different piece of work, is billed and reported by the physician and must be documented as such.