How prior authorization requests work
A prior authorization request is typically submitted by the treating provider before a planned service, describing the diagnosis, proposed treatment, and supporting clinical rationale. The payer (or a utilization review vendor acting on the payer's behalf) evaluates the request against applicable treatment guidelines and either approves it, denies it, or requests additional information before making a determination. In some jurisdictions, unresolved or contested requests can escalate to a formal dispute or peer-to-peer review process, with statutory timeframes governing how quickly a decision must be issued.
Codes and services commonly subject to prior auth
Not every service requires prior authorization. Jurisdictions and payers typically maintain a defined list of procedures, code categories, or treatment types that trigger the requirement, often concentrated in higher-cost or higher-variability categories such as surgery, advanced imaging, certain injections, durable medical equipment, and extended courses of therapy. Emergency treatment is commonly exempted from prospective authorization requirements, though it may still be subject to retrospective medical necessity review.
What happens when prior auth is missing
When a service that requires prior authorization is rendered without an approved request, the associated charges are frequently denied outright during bill review, independent of whether the treatment would have otherwise met the medical necessity standard. Some jurisdictions allow a provider to submit a retrospective request or supporting documentation after the fact, while others treat the missing authorization as an absolute bar to payment. Because the consequences of a missing authorization can be more severe than a straightforward necessity dispute, correctly identifying which services require prior authorization, in which jurisdiction, is a meaningful part of both provider revenue cycle management and payer bill review.
Prior authorization vs. retrospective utilization review
Prior authorization is inherently prospective: it happens before treatment. Retrospective utilization review, by contrast, evaluates medical necessity after treatment has already occurred, typically during the bill review and payment process. A service without a prior authorization requirement can still be denied on medical necessity grounds through retrospective review, and a service that received prior authorization can, in some circumstances, still be subject to further review if the treatment actually rendered deviated materially from what was authorized.
How BillSentry applies prior authorization rules
BillSentry automatically identifies the applicable workers' compensation reimbursement methodology and calculates the allowed amount at the bill-line level, flagging where a billed service required prior authorization and surfacing missing or incomplete authorization documentation as part of the review.
Every result is documented as a RuleTrace™, showing the specific authorization requirement and the rationale behind any resulting denial or reduction.