It is the responsibility of CMS to administer Medicare and other federally mandated healthcare programs throughout the United States. Medicare prohibits payment for services and items deemed by local Medicare Carriers as not medically reasonable and necessary for the diagnosis or treatment of an illness or injury, so here documentation is essential for claims to be paid.
There are a couple of points that a physician needs to ensure like only tests that are medically necessary in diagnosing or treating their patients should be asked for, correct ICD-9 codes to be used for patient files and test request forms, advance beneficiary notes to be signed by patients in case service gets denied.