The Independent Review Entity (IRE), explained

By the time a case reaches the IRE, it has already been reviewed once by the plan itself — this is the first review by an organization with no financial stake in the outcome, which is a meaningfully different kind of scrutiny than a plan reconsidering its own decision.

The IRE's decision is also the point at which the case becomes eligible to move further — to an ALJ hearing — once the amount-in-controversy threshold is met, so an IRE denial isn't a dead end even when it upholds the plan.

You don't file anything to reach the IRE — the plan is required to forward the case automatically once it upholds its own denial at reconsideration, or fails to decide the reconsideration in time. If you believe your case should have been forwarded and hasn't been, that's worth a direct call, since an automatic step that silently doesn't happen is a real, correctable error, not something to simply wait out.

The IRE's own decision letter will explain, in writing, the basis for its ruling and cite the specific Medicare rule it applied — reading that letter carefully is worth it even when the outcome is unfavorable, since it tells you exactly what an ALJ would also be looking at if the case goes further.

Like reconsideration, the IRE level is a genuine fresh review — new evidence submitted at this stage is considered, not just whatever the plan originally had on file.

Unlike a plan's own reconsideration, the IRE has no ongoing relationship with the plan and no financial incentive tied to the outcome — its only role is to apply the Medicare rule correctly.