Prior authorization
DefinitionApproval a plan requires before a service for it to be covered. Most plans don't require it for routine MNT, but some do, often past a visit threshold.
Prior authorization (also called preauthorization or precertification) is a plan's decision, before the service, that the service is medically necessary and covered (HealthCare.gov glossary). An approval normally covers a set number of visits or units over a date range; care outside either limit can deny.
For nutrition practices:
- Original Medicare MNT coverage runs on the physician referral and annual hour limits; CMS's MNT billing instructions don't add a prior authorization step (Ch. 4, §300).
- Medicare Advantage and Medicaid managed care plans may require it. Under CMS's 2024 interoperability and prior authorization rule, these payers must decide standard requests within 7 calendar days and expedited requests within 72 hours starting in 2026, and give a specific reason for denials (CMS-0057-F fact sheet).
- Commercial plans vary by plan; employer plans are not covered by that CMS rule.
Ask during every verification call, record the authorization number and its dates, and put the number on the claim. In-network, a no-auth denial is usually a write-off, not a patient balance.