They sound interchangeable and they are not, and the difference decides whether you get an estimate or an actual approval. Predetermination tells you what should be covered. Preauthorization is the plan agreeing in advance to pay. This guide covers what each one is, when to send them, how long they take, and the trap that catches practices: a predetermination is not a guarantee of payment.
Last updated July 2026 · Reviewed by the PracticeAlpha billing team
The short answer. A predetermination is a formal inquiry that confirms the patient is covered, that the treatment is a benefit, and gives a written estimate of what they will owe. It is a planning tool, not a promise. A preauthorization is written advance approval that a specific service will be covered, and in many states the plan is required to honor it. So predetermination answers "roughly what will this cost the patient," and preauthorization answers "will you agree to pay for this before I do it." Knowing which one a situation needs is what keeps big cases from turning into billing surprises.
A predetermination is a request you send the plan before treatment. It confirms three things: that the patient is a covered enrollee, that the proposed treatment is a covered benefit for them, and what their likely out-of-pocket cost will be. That makes it invaluable for the treatment-plan conversation, because the patient sees a real number before committing to a crown or a larger case.
The catch is in what it is not. A predetermination is a formal inquiry into eligibility, not a guarantee of payment. Final payment still depends on the patient's benefits at the time of service, their remaining annual maximum, frequency and waiting-period rules, and the documentation on the actual claim. Treat it as a strong estimate, not a locked-in promise, and it does its job well.
You will also hear the term pre-treatment estimate, or pre-estimate. In practice it means much the same thing as a predetermination: a non-binding estimate of coverage and patient cost before treatment. Some carriers use the terms interchangeably, others treat the pre-estimate as the lighter, informal version. Either way it sits in the same category, useful for planning and patient conversations, not a promise to pay. What you should not confuse it with is a preauthorization, which is the one that actually carries weight.
A preauthorization goes a step further than an estimate. It is the plan indicating in advance that a specific planned service will qualify as a covered benefit, and in many states the plan is then required to pay for the treatment it preauthorized. That is a materially stronger position than a predetermination, because it is closer to a commitment than a guess.
The flip side is that some services require it. When a procedure needs preauthorization and it is not obtained, the claim can be denied even though the treatment was otherwise covered. Which services require it varies by plan, so the reliable move is to confirm the plan's rules during verification and get the approval in hand before the procedure, not after.
Missing a required preauthorization, or quoting off a predetermination as if it were a guarantee, both end in surprise balances. We handle both correctly during verification.
See our verification serviceThe two are not mutually exclusive. On a big case you might send a predetermination for the patient estimate and obtain a preauthorization where the plan demands one. Both are also central to cross-coding to medical insurance, where medical plans frequently require pre-approval before surgery.
Neither is instant, which is the practical reason to plan ahead. A predetermination generally comes back in anywhere from a few days to about two weeks, depending on the carrier and the service. A preauthorization can take longer, commonly somewhere between 5 and 30 days depending on the procedure and the plan.
That lead time is why both are requested well before the planned treatment date rather than the week of. Building the request into the treatment-planning step, instead of scrambling once the appointment is booked, keeps the schedule moving and the patient informed. If waiting on approvals is slowing your treatment acceptance or your claims, a free AR analysis can show where the process is costing you.
A predetermination is a formal inquiry to the plan before treatment that confirms the patient is a covered enrollee, that the proposed treatment is a covered benefit, and gives a written estimate of the patient's likely out-of-pocket cost. It is useful for planning and patient conversations, but it is an estimate of eligibility, not a guarantee that the claim will be paid.
A predetermination confirms coverage and estimates the patient's share; it does not lock in payment. A preauthorization is written advance approval that the specific planned service will be covered, and in many states the plan is required to honor it. In short, predetermination is an estimate of what should be covered, preauthorization is approval to proceed.
Predeterminations are commonly recommended for larger treatment plans, often those above a few hundred dollars, and for major or costly procedures where the patient needs an accurate estimate before committing. Sending one avoids surprise balances and difficult conversations after treatment, which is why many offices use them as standard practice on bigger cases.
Some services require advance approval before they are performed, and skipping it can lead to a denial even when the treatment was covered. Which procedures need preauthorization varies by plan, so the reliable step is to check the specific plan's rules during verification. When a service requires it, obtaining it first is what protects the claim.
A predetermination generally takes anywhere from a few days to about two weeks, depending on the carrier and the service. A preauthorization can take longer, commonly somewhere between 5 and 30 days depending on the procedure and the plan. Because both take time, they are requested well before the planned treatment date, not at the last minute.
No. A predetermination confirms eligibility and estimates coverage based on the information available, but final payment still depends on the patient's benefits at the time of service, remaining annual maximum, frequency and waiting-period rules, and the documentation on the actual claim. It is a strong planning tool, not a promise, which is why the claim still has to be filed correctly.
Free AR analysis. We show you where slow or missing predeterminations and preauthorizations are stalling treatment acceptance and delaying claims, and what fixing it recovers. 30 minutes. No commitment.