Medicare's CPAP rules: the 12-week trial and the 4-hour rule

Before you get a machine

• Your doctor sees you in person to check for sleep apnea before your sleep test.^[1]
• The test is scored with the apnea-hypopnea index (AHI). It counts breathing pauses and shallow breaths per hour of sleep.^[1]
• An AHI of 15 or more qualifies. So does 5 to 14 if you also have sleepiness, memory or mood problems, trouble sleeping, high blood pressure, heart disease or a past stroke.^[1]
• Your supplier must show you, or the person who helps you, how to use and care for the machine.^[1]

The first three months

• Medicare covers a 12-week trial of the machine and its supplies.^[2]
• To pass, use the machine 4 hours or more a night, on at least 70% of nights, over any 30 days in a row.^[1]
• For most people, 70% of 30 nights means at least 21 nights.^[1]
• Medicare needs objective proof of your use, and your doctor must review it. Your word alone is not enough.^[1]

Step by step

1. Start using the machine every night, for the whole night if you can.^[1]
2. Book a follow-up visit for between day 31 and day 91 after you start.^[1]
3. At that visit, your doctor notes that your symptoms are better and reviews your use record.^[1]
4. If both are on record, Medicare keeps paying after the first three months.^[1]

If the trial doesn't work out

• If you don't meet the rules, Medicare stops paying for the machine and its supplies.^[1]
• You can qualify again. You need a new in-person visit and a new sleep test done in a sleep lab.^[1]
• If the follow-up visit is late but shows the machine helps, coverage starts again from that visit.^[1]

Moving to a bilevel machine

• Medicare covers a bilevel machine when a regular CPAP was tried and did not help. The mask and settings must have been right.^[1]
• Switching to bilevel does not need a new first visit or a new sleep test.^[1]

More in this guide

• Sleep apnea machines: overviewHow CPAP machines work and how Medicare covers them. Learn the 12-week trial, the 4-hour rule and the 13-month rental. Then see how the main brands differ.
• What CPAP costs with Medicare, and how often you get new suppliesThe 20% you pay and the 13-month rental. Then how often Medicare pays for new masks, hoses and filters.
• CPAP masks, humidifiers and cleaningThe main mask types, how humidifiers work, and what the government says about cleaning your machine.
• Traveling with a CPAP, and fixing common problemsAirport screening, carry-on rules and using a CPAP on a plane, plus the first things to check when therapy feels wrong.