Retrospective (retro) authorization

What it is

Retrospective (retro) authorization is plan approval requested AFTER the service has been delivered. It applies when prior authorization was required but could not have been obtained in advance — emergency care, post-stabilization care, urgent procedures, or services where the need only became apparent intra-operatively. Some plans have a formal retro-auth process documented in their provider manual; others handle it through the standard appeal process.

Who can use it

Providers (typically billers / coders) — the patient is not usually the party requesting retro-auth, though the patient bears the consequences if it's not granted.

When to use it

When (a) prior auth was required but the service was delivered without it due to genuine clinical urgency, (b) the original authorization didn't cover everything that turned out to be needed (intra-operative findings), or (c) the plan denied the auth in advance but the service was clinically essential.

Steps

1. Identify the plan's retro-auth window. Provider manuals usually specify a window — often 14-30 days post-service — within which retro-auth requests will be considered.
2. Document the urgency. The chart must clearly show why prior auth couldn't be obtained — emergency presentation, post-stabilization, intra-operative finding, etc.
3. Submit the auth request retrospectively. Most plans use the same auth submission portal. Mark as retrospective and include the clinical rationale.
4. Track the decision. Plans typically respond within their normal auth-decision timeline. If denied, proceed to formal appeal citing the urgency and any relevant federal protections (NSA emergency, MHPAEA, Prudent Layperson Standard).

Key deadlines