In fee-for-service medicine:
Diagnosis coding establishes medical necessity, and may be the reason for a denial, particularly for diagnostic tests or procedures. Services with national or local coverage policies often have specific diagnosis codes that are required for payment.
In risk based contracts or Accountable Care Organizations (ACOs):
Payers assess the acuity of a panel of patients, and use that acuity along with age/gender distribution, cost, quality and outcomes, to provide incentive payments or decrease payments at the end of a contract year.
What should physicians and other practitioners do?
Document underlying medical problems that require or affect treatment—even if you are not treating the problem at this visit.