Medicare CPAP coverage and the 90-day rule (2026)

Medicare coverage for CPAP comes with a probation period. The first 12 weeks are a trial. Whether Medicare keeps paying depends on two things: data your machine records, and an in-person visit inside a fixed window. This guide sets out the rules from medicare.gov and the DME contractors’ Local Coverage Determination, LCD L33718, Positive Airway Pressure (PAP) Devices for the Treatment of Obstructive Sleep Apnea.

Step 1: qualifying for the trial

Under L33718, a CPAP device (E0601) is covered for obstructive sleep apnea when all three of these are met:

1. In-person evaluation first. Your treating practitioner sees you in person, before the sleep test, to assess you for OSA.
2. A qualifying sleep test. One of:
   • AHI or RDI ≥ 15 events per hour with at least 30 events; or
   • AHI or RDI 5–14 with at least 10 events, plus documented excessive daytime sleepiness, impaired cognition, mood disorders or insomnia, or hypertension, ischemic heart disease or a history of stroke.
3. Instruction. The supplier has shown you or your caregiver how to use and care for the equipment.

CMS’s supplier guidance lists the sleep tests that count: an attended in-lab polysomnogram, or an unattended home sleep test on a Type II, Type III, or Type IV device measuring at least 3 channels (CMS MLN).

Step 2: the 12-week trial and the adherence rule

Medicare.gov says Medicare may cover a 12-week trial of CPAP, including devices and accessories. It continues coverage afterwards only if you meet your provider in person and they document that you meet certain conditions and the therapy is helping.

The LCD spells out those conditions. No sooner than day 31 and no later than day 91 after starting therapy, your treating practitioner must re-evaluate you and document that you are benefiting. That requires both of these (L33718):

1. An in-person clinical re-evaluation documenting that your OSA symptoms improved; and
2. Objective evidence of adherence, reviewed by the practitioner. The LCD defines adherence as:

use of PAP ≥4 hours per night on 70% of nights during a consecutive thirty (30) day period anytime during the first three (3) months of initial usage.

In practice, that is at least 21 nights at 4 hours or more within any 30-day stretch. If the re-evaluation happens after day 91 but shows both criteria are met, coverage resumes from the date of that visit. If the criteria aren’t met, continued coverage of the device and accessories is denied.

How to pass

• Use it every night from night one. The 30-day window can be any consecutive 30 days in the first three months, so a bad first week isn’t fatal. Waiting is the risk.
• Count hours, not nights. A night under 4 hours doesn’t count toward the 70%.
• Fix mask problems early. Leaks and discomfort are the usual reason people stop. Ask your supplier for a refit in the first two weeks.
• Book the follow-up for day 31 or later. A visit before day 31 doesn’t satisfy the window.

If you fail the trial

Under L33718, you can re-qualify, but you need both an in-person re-evaluation to find the cause of the failure and a repeat sleep test in a facility (Type 1 study). That repeat can be a diagnostic, titration or split-night study.

When Medicare covers BiPAP instead

A bi-level device without backup rate (E0470) is covered for OSA only if you meet the CPAP criteria above and a CPAP (E0601) “has been tried and proven ineffective”. That trial can be in a facility titration or at home, despite proper mask fitting and pressure settings. A bi-level device with a backup rate (E0471) is not covered when the primary diagnosis is OSA (L33718).

What you pay and when you own it

Per medicare.gov:

• You pay 20% of the Medicare-approved amount after the Part B deductible, if the supplier accepts assignment. This covers the machine rental and related supplies such as masks and tubing.
• Medicare pays the supplier to rent the machine for 13 continuous months. After that, you own the machine.
• If a supplier doesn’t participate in Medicare or won’t accept assignment, you may be charged more, and may have to pay upfront and be reimbursed later.

Already had CPAP before joining Medicare

Medicare.gov says Medicare may cover a rental or replacement machine or accessories if you had CPAP before Medicare and meet certain requirements. CMS’s supplier guidance says you need documentation of a sleep test from before enrollment that meets current criteria, plus an in-person evaluation after enrolling that documents your OSA diagnosis and that you still use the device (CMS MLN).

Replacing a machine

CMS’s supplier guidance states that a PAP device lost, stolen or irreparably damaged in a specific incident during its 5-year reasonable useful lifetime can be replaced without a new evaluation, sleep test or trial. After 5 years, replacement needs an in-person evaluation documenting continued use and benefit, but no new sleep test or trial (CMS MLN).

Verdict

Treat the first 90 days as the part that decides your coverage. Get the in-person evaluation before the sleep test, and use the machine at least 4 hours a night from the first night. Book the follow-up visit between day 31 and day 91, and bring the usage data. Get those right and Medicare covers 80% of the approved rental, and the machine is yours after 13 months. HHZ’s US CPAP guide covers which machines to ask your supplier about.

Comfort problems that threaten adherence

If something is stopping you reaching 4 hours a night, fix it early: dry mouth, mask leaks, stuffy nose, swallowing air, rainout. If your machine reports a high AHI, see high AHI on CPAP.

Bilevel and ASV

If CPAP doesn’t work for you, Medicare’s bilevel and ASV rules are in BiPAP and ASV: Medicare rules. For tracking your usage hours, see myAir vs OSCAR.

Related diagnosis and coverage guides

See home sleep test vs in-lab, Medicare Advantage vs Original Medicare for DME, Medicaid DME coverage and VA CPAP benefits.

See also: Medigap and DME costs and DME assignment explained.

See also: How to appeal a Medicare DME denial.