Who Qualifies for CPAP Under Medicare? Sleep Test Rules

Updated November 2026. Written by Matteo Grassi, clinical psychologist and cofounder of HANA Health.

Medicare covers CPAP for adults with obstructive sleep apnea (OSA) after an in person exam by the treating practitioner and a valid sleep test. The test must show an apnea hypopnea index (AHI) of at least 15 events an hour, or 5 to 14 with documented symptoms or a heart or stroke history. Coverage starts with a 12 week trial.

Most CPAP denials I hear about start before the machine ships. The paperwork that proves a patient qualifies is easy to lose, and Medicare reviewers look for it first.

Key facts

• Medicare's national policy, NCD 240.4, limits CPAP coverage to an initial 12 week period for adults with OSA.
• The treating practitioner must examine the patient in person before the sleep test, according to the CMS compliance tips page for CPAP.
• An AHI or RDI of 15 or more events an hour with at least 30 events qualifies on its own.
• An AHI or RDI of 5 to 14 events an hour with at least 10 events qualifies only with documented symptoms or conditions such as hypertension, ischemic heart disease or a prior stroke.
• The 2024 CMS data put the CPAP improper payment rate at 12.5%, about $146.1 million, and 71.2% of those errors were insufficient documentation.
• A patient who fails the 12 week trial needs an in person reevaluation and a repeat facility based (Type I) sleep study before a new trial can start, per LCD L33718 as quoted by the AASM.
• Medicare.gov says beneficiaries pay 20% of the approved amount after the Part B deductible, and rental runs 13 months.

What does Medicare require before it covers CPAP?

Medicare requires three things before the first claim: an in person clinical evaluation, a qualifying sleep test, and documented device instruction. Continued coverage after week 12 is a separate step.

The sequence matters. CMS lists the practitioner's in person exam as happening before the sleep test, so the evaluation can't be reconstructed later from the sleep report. The test then has to be one Medicare accepts and has to meet an AHI threshold. Last, whoever supplies the device must teach the patient or a caregiver how to use and care for it, and document that teaching.

Here's the checklist most suppliers work from:

1. An in person evaluation by the treating practitioner to assess for OSA, dated before the sleep test.
2. A Medicare accepted sleep test with results in the record.
3. AHI or RDI results that meet one of the two coverage thresholds.
4. A standard written order that names the device and carries the practitioner's signature and date.
5. Documented instruction for the patient or caregiver on proper use and care.

If any of these is missing, a reviewer can deny the claim as not reasonable and necessary, even when the patient clearly has sleep apnea and uses the device every night.

Which sleep tests does Medicare accept for CPAP?

Medicare accepts a sleep lab polysomnogram (PSG) attended by a qualified practitioner, or an unattended home sleep test (HST) using a Type II, Type III, or Type IV device that records at least 3 channels. That's the list on the CMS CPAP compliance page.

A few details trip people up. The test has to be ordered by the patient's treating physician and furnished under appropriate supervision, which is the language in NCD 240.4. A consumer wearable or an app estimate isn't on the list. And the AHI is an average of events per hour, so a very short recording can fail on volume alone. If the AHI or RDI rests on less than 2 hours of continuous recorded sleep, the total event count has to be at least what a 2 hour period would have required.

CMS also defines the events. An apnea is a stop in airflow for at least 10 seconds. A hypopnea is an abnormal breathing event of at least 10 seconds with at least a 30% drop in chest or abdominal movement or airflow and at least 4% oxygen desaturation. If a sleep report uses a different hypopnea rule, the numbers may not match what Medicare counts.

What AHI does Medicare require to cover CPAP?

Medicare covers an initial 12 week CPAP trial at an AHI or RDI of 15 or more events an hour with at least 30 events. At 5 to 14 events an hour it requires at least 10 events plus documented symptoms or a qualifying condition.

Here are the two paths, step by step:

• Path one, AHI 15 or higher: at least 30 recorded events. No symptom documentation is needed to meet the AHI test.
• Path two, AHI 5 to 14: at least 10 recorded events, plus one of two documented groups.
• Symptom group: excessive daytime sleepiness, impaired cognition, a mood disorder, or insomnia.
• Condition group: hypertension, ischemic heart disease, or a history of stroke.

The second path fails most often on documentation, not on the number. A patient with an AHI of 9 and a blood pressure diagnosis qualifies, but only if the chart shows the diagnosis and the practitioner links it to the OSA workup. Here's a worked example. A patient's home test shows an AHI of 11 with 22 events and the chart notes treated hypertension. That meets path two. The same patient with an AHI of 11 and nothing documented does not.

What happens after the first 12 weeks?

Coverage continues only if the practitioner documents benefit and adherence. NCD 240.4 says CPAP is covered after the trial "only for those beneficiaries diagnosed with OSA who benefit from CPAP during this 12 week period."

The mechanics are covered in our guides to Medicare's CPAP compliance requirements and the CPAP face to face reevaluation. In short, the practitioner sees the patient in person between day 31 and day 91 and documents improved symptoms, plus objective use of 4 or more hours a night on 70% of nights in a consecutive 30 day window. Once that is met, the supplier can bill months 4 through 13. How those 13 rental months work is in our piece on the 13 month capped rental.

One more point on timing. Per Noridian's billing guidance, if the in person visit happens after day 91 but the patient met the adherence standard in the trial window, suppliers holding claims can add the KX modifier for month 4 and beyond.

What if a patient fails the trial or switches to bilevel?

A patient who fails the 12 week trial can requalify, but only with an in person reevaluation to find out why therapy failed and a repeat facility based Type I sleep study. That study can be a diagnostic, titration, or split night study. The wording comes from LCD L33718, quoted by the AASM.

Billing pauses in the meantime. Noridian's guidance says suppliers can't bill with the KX modifier during the second trial, and can resume only after the new trial ends, adherence is shown, and a new in person visit documents benefit. Noridian publishes this for its DME jurisdiction. The AASM has reported that the sleep study rule in L33718 appears to conflict with another policy, so check with your MAC before relying on a retest.

A bilevel device (E0470) adds a requirement. Coverage criteria for CPAP must be met first, then a CPAP device has to be tried and proven ineffective. That means a documented failure to reach therapeutic goals during a facility titration or at home despite proper mask fit and appropriate pressure settings.

What about patients who had CPAP before Medicare?

For patients who got a device before enrolling in fee for service Medicare, CMS requires two things. First, documentation of a pre enrollment sleep test that meets the AHI criteria in effect when the patient seeks coverage. Second, an in person evaluation after enrollment documenting the OSA diagnosis and that the patient still uses the device.

If either is missing, the claim is denied. When both are met, CMS says there is no requirement for a new reevaluation or objective adherence documentation. Replacement rules for lost, damaged or aging devices are in our guide to replacing a CPAP under Medicare.

What this means for your DME

Treat the intake file as the audit file. Before you ship, confirm the dated in person exam, the sleep report with AHI and event counts, the order, and the instruction note. For the 5 to 14 AHI group, confirm the symptom or condition documentation is in the chart, not only in the referral.

The scale is large. An estimated 29.4 million U.S. adults have OSA, per a 2016 Frost and Sullivan analysis for the AASM, and the estimate has been described as about 80% undiagnosed in a 2020 position paper. That's an older estimate, so treat it as a rough size, not a current count. Once qualification is clean, adherence is what decides whether rental months get paid. HANA builds outreach for DMEs that supports patients through the first 90 days; see HANA for sleep and PAP.

Frequently asked questions

Does Medicare cover a CPAP without a sleep test?

No for routine coverage. Coverage requires a qualifying sleep test. NCD 240.4 allows limited coverage for patients enrolled in a research study that meets CMS standards, but that isn't an everyday route.

Does a patient need a new sleep test every time they replace a CPAP?

No. CMS says replacing a device lost, stolen or irreparably damaged in the 5 year useful lifetime needs no new evaluation, sleep test or trial. After 5 years, an in person visit must document continued use and benefit, with no new sleep test or trial.

What is the difference between AHI and RDI?

Both count breathing events per hour. CMS lets either number meet the coverage thresholds. Reports label them differently depending on the device and scoring method.

Does a home sleep test qualify for CPAP coverage?

Yes, if it uses a Type II, Type III or Type IV device that records at least 3 channels. A Type I lab study is required only when requalifying after a failed trial.

Who pays for CPAP under Medicare after I qualify?

After the Part B deductible, the patient pays 20% of the approved amount if the supplier accepts assignment, according to Medicare.gov. Medicare pays rental for 13 continuous months, after which the patient owns the machine.

Sources

1. Centers for Medicare and Medicaid Services, "Continuous Positive Airway Pressure Devices and Accessories," Medicare Learning Network compliance tips, 2024 reporting period.
2. Centers for Medicare and Medicaid Services, "Positive Airway Pressure (PAP) Devices: Complying with Documentation and Coverage Requirements," ICN 905064, 2016.
3. American Academy of Sleep Medicine, "AASM continues to work toward rectifying Medicare audit issue," 2022 (quotes LCD L33718).
4. Noridian Healthcare Solutions, "Correct Billing: Continued Coverage for PAP Devices for the Treatment of OSA," JA DME, 2019.
5. Medicare.gov, "Continuous Positive Airway Pressure (CPAP) therapy."
6. American Academy of Sleep Medicine, "Economic burden of undiagnosed sleep apnea in U.S. is nearly $150B per year," 2016.
7. Schwartz et al., "American Academy of Dental Sleep Medicine Position on the Scope of Practice for Dentists Ordering or Administering Home Sleep Apnea Tests," Journal of Dental Sleep Medicine, 2020.

This article is educational and isn't billing, coding, clinical or legal advice. Check current CMS guidance and your MAC before you bill. If you run a DME and want to talk through adherence outreach, book a discovery call.