Prior authorization is your plan’s approval before care starts. For detox, residential care and partial hospitalization, plans often approve a few days at a time, then check whether your loved one still meets their medical necessity criteria before approving more. A seven-day approval usually means the plan will look again before day seven.
Many families hear “approved” and assume the whole stay is paid for. Then, a few days in, the program says the plan wants an update, or won’t approve more days. Knowing how the process works helps you ask the right questions before admission and act quickly if days are cut short.
What do the terms mean?
You’ll usually run into all three during a single stay.
| Term | What it means | Who does it |
|---|---|---|
| Prior authorization | The plan’s decision, before care starts, that a service is medically necessary. Also called preauthorization, prior approval or precertification.1 | The program usually asks; the plan decides |
| Medical necessity | Care needed to diagnose or treat a condition that meets accepted standards of medicine.2 The plan applies its own written criteria to decide.4 | The plan’s reviewers |
| Utilization review | The plan’s checks on whether care is medically necessary. Reviews during a stay are often called concurrent review: the program reports progress, and the plan decides whether to approve more days. | The program reports; the plan decides |
Why did insurance approve only 7 days?
Approval for higher levels of care usually comes in pieces. A short approval doesn’t cap the stay, but it isn’t a promise of more, either.
This matches how addiction care is meant to work. Under the American Society of Addiction Medicine (ASAM) Criteria, length of care follows a person’s progress and needs rather than a fixed number of days: someone who improves can move to less intensive care, and someone who doesn’t may need more.3 Each review is the plan asking that same question as the one paying.
How do plans decide what’s medically necessary?
They compare your loved one’s clinical information against written criteria. Many plans use the ASAM Criteria;3 some use others, so ask which ones yours uses. Reviewers look at withdrawal risk, physical and mental health, safety, progress in treatment, and whether home is a safe place to recover, the same ground an assessment for level of care covers.
Under federal parity law, you can ask for two things. The plan’s medical necessity criteria for substance use benefits must be available to any current or potential member on request, and so must the reason for any denial of payment.4 If an internal appeal fails, most plans let denials that involve medical judgment go to an independent external review.910
Does prior authorization mean the plan will pay?
Not necessarily. HealthCare.gov says preauthorization isn’t a promise your plan will cover the cost.1 A claim can still be denied later, for example if coverage lapsed, the program was out of network, or the service wasn’t a covered benefit.8
Before signing the financial agreement, get the program to put in writing what you’ll owe if the plan stops approving days and your loved one stays. Our pages on what a benefits check really confirms and a worked cost example show how denied days change the bill.
How fast does the plan have to decide?
It depends on the coverage, and urgent requests move faster.
| Coverage | Urgent request | Standard request |
|---|---|---|
| Most private plans | Decision, with a written reason if denied, within 72 hours8 | Within 15 days for a prior authorization8 |
| Medicare Advantage, Medicaid and CHIP plans (since January 1, 2026) | Decision within 72 hours6 | Decision within 7 calendar days6 |
Your plan documents and any denial letter list the exact deadlines. If waiting could seriously jeopardize your loved one’s health, ask the program to mark the request, or an appeal, as urgent (expedited).8
Since January 1, 2026, a federal rule requires Medicare Advantage plans, Medicaid and CHIP programs, and plans sold on HealthCare.gov to give the provider a specific reason when they deny a prior authorization, and to post prior authorization statistics on their websites each year.6
Can a plan be stricter about addiction care than other care?
Not if it’s covered by federal parity law. Prior authorization and other medical management count as “nonquantitative treatment limitations,” and a plan can’t apply them to substance use treatment more strictly than to comparable medical or surgical care.5
That gives you a pointed question: “Do you review a comparable medical stay, such as inpatient rehabilitation after surgery, this often and in this much detail?” If the answer suggests addiction care gets tougher treatment, raise it in an appeal. Our page on appeals and parity complaints explains how.
The plan approved only a few days. What now?
The plan approved only a few days. What now?
InteractiveWhere is the plan’s decision right now?
See possible outcomes
- Get ready for the review Ask the program when the review is and how you’ll hear the result. Tell the care team what you’ve seen at home; it can fill out the clinical picture.
- Note the new end date Write down the new end date and the reference number, and ask what discharge planning has started.
- Line up the next level before discharge Make sure the next level of care, such as PHP or IOP, is approved and scheduled with no gap, and that any medication will continue.
- Ask for the reason and appeal Get the denial and the criteria in writing. Ask whether the program’s doctor can speak with the plan’s reviewer, and whether the appeal can be expedited.
- Ask the care team directly Ask the program’s clinical staff whether they agree with the plan’s decision and why. Your loved one may need to sign a release before staff can talk with you.
What to ask before and during a stay
Take this list to your calls with the plan and the program. Each time you talk with the plan, note the date, the representative’s name and the reference number, and keep every letter. You’ll need them for an appeal.
Prior authorization questions for the plan and the program
- Before admission
- During the stay
- If more days are denied
A denial is a payment decision, not a medical order to leave. If detox is cut short while your loved one still has withdrawal symptoms, ask the medical team whether discharge is safe, and know the withdrawal warning signs.
Frequently asked questions
What happens if my loved one's insurance changes during treatment?
The new plan may need its own authorization. In a June 2025 voluntary pledge, many large plans said they would honor existing authorizations during insurance transitions,7 but details vary. Call the new plan right away and ask how it will handle the current stay.
Do addiction medications need prior authorization?
Sources
- HealthCare.gov — Preauthorization (glossary). healthcare.gov/glossary/preauthorization/ — accessed Oct 2026
- HealthCare.gov — Medically necessary (glossary). healthcare.gov/glossary/medically-necessary/ — accessed Oct 2026
- American Society of Addiction Medicine — The ASAM Criteria. asam.org/asam-criteria — accessed Oct 2026
- Centers for Medicare & Medicaid Services — Fact sheet: The Mental Health Parity and Addiction Equity Act of 2008 (MHPAEA). cms.gov/newsroom/fact-sheets/mental-health-parity-and-addiction-equity… — accessed Oct 2026
- Centers for Medicare & Medicaid Services — The Mental Health Parity and Addiction Equity Act (MHPAEA). cms.gov/marketplace/private-health-insurance/mental-health-parity-addi… — accessed Oct 2026
- Centers for Medicare & Medicaid Services — Fact sheet: CMS Interoperability and Prior Authorization Final Rule CMS-0057-F (2024). cms.gov/newsroom/fact-sheets/cms-interoperability-prior-authorization-… — accessed Oct 2026
- Centers for Medicare & Medicaid Services — HHS Secretary Kennedy, CMS Administrator Oz Secure Industry Pledge to Fix Broken Prior Authorization System (press release, June 23, 2025). cms.gov/newsroom/press-releases/hhs-secretary-kennedy-cms-administrato… — accessed Oct 2026
- HealthCare.gov — Internal appeals. healthcare.gov/appeal-insurance-company-decision/internal-appeals/ — accessed Oct 2026
- HealthCare.gov — External review. healthcare.gov/appeal-insurance-company-decision/external-review/ — accessed Oct 2026
- HealthCare.gov — How to appeal an insurance company decision. healthcare.gov/appeal-insurance-company-decision/ — accessed Oct 2026
- Centers for Medicare & Medicaid Services — Fact sheet: 2026 CMS Interoperability Standards and Prior Authorization for Drugs Proposed Rule (CMS-0062-P), April 10, 2026. cms.gov/newsroom/fact-sheets/2026-cms-interoperability-standards-prior… — accessed Oct 2026