Medicare covers one sleep study every five years, with some exceptions for certain diagnoses
Medicare Part B pays for a sleep study (also called polysomnography) once every five years under standard coverage rules. If you have been diagnosed with obstructive sleep apnea and need a second study to test a new treatment or device, Medicare may cover it sooner — but you will need your doctor to document the medical reason and submit it with the claim. The five-year window resets from the date of your previous study, not from the calendar year.
The coverage applies only to studies done in a sleep lab or, in some cases, at home with equipment your doctor orders. Studies ordered for screening purposes — when you have no symptoms or diagnosis yet — are not covered. You must have a doctor's order, and the lab must be Medicare-certified.
Key Takeaways
- Medicare covers one sleep study every five years; the clock starts from the date of your previous study, not January 1st.
- A second study within five years is possible if your doctor documents a new diagnosis, a change in your condition, or the need to test a new treatment.
- Home sleep tests are covered in some situations, but your doctor must order the equipment and a Medicare-certified provider must conduct it.
- You pay 20 percent of the Medicare-approved amount after you meet your Part B deductible; the lab cannot charge you more than that approved amount.
When Medicare will pay for a second study before five years
If your first sleep study confirmed obstructive sleep apnea and your doctor now wants to test whether a CPAP machine or oral appliance is working, Medicare may cover a second study sooner than five years. Your doctor must write a note explaining why the second study is medically necessary — for example, "to assess response to CPAP therapy" or "to evaluate a new oral appliance." This note goes to the lab, which includes it with the claim to Medicare.
A second study may also be covered if you have a new diagnosis that requires sleep testing — such as central sleep apnea or narcolepsy — even if you had a study for a different reason within the past five years. Again, your doctor's documentation of the new condition is what makes the difference. Without that written explanation, the claim will likely be denied as a duplicate within the five-year window.
What you pay out of pocket
After you meet your Part B deductible for the year, you pay 20 percent of the Medicare-approved amount for the sleep study. The actual cost of a sleep study varies widely — from roughly $1,000 to $3,000 or more depending on the lab and your location — but Medicare sets its own approved amount, which is usually lower. Your 20 percent coinsurance is based on that approved amount, not the lab's full charge.
If you have a Medigap or Medicare Advantage plan, your out-of-pocket cost may be lower or covered entirely, depending on your plan's terms. Check your plan documents or call the plan to find out what you will owe. The sleep lab should give you an estimate before the study, based on your coverage.
Home sleep tests versus lab studies
Medicare covers home sleep apnea tests (HSAT) in limited situations. Your doctor can order a home test device if you cannot travel to a lab or have a condition that makes a lab visit unsafe. The device is mailed to you, you use it at home for one or more nights, and you mail it back. A technician reviews the results, and your doctor gets a report.
Home tests are less expensive than lab studies and count toward your five-year limit just as lab studies do. However, not all home tests are covered — Medicare has specific rules about which devices and which clinical situations may have access to. Your doctor and the testing company will know whether your situation meets those rules. If it does not, you may be asked to pay out of pocket or to go to a lab instead.
How to make sure your claim is processed correctly
Before your sleep study, confirm with the lab that it is Medicare-certified. Ask the lab to verify your coverage and give you a written estimate of what you will owe. Bring your Medicare card and any secondary insurance card to the appointment.
If your study is a second one within five years, make sure your doctor's office submits the medical necessity letter to the lab before the test. This letter should be in your chart at the lab and attached to the claim when it goes to Medicare. Without it, the claim will be denied, and you may be billed for the full cost.
After the study, ask the lab for a copy of the claim they submitted to Medicare and the explanation of benefits (EOB) you receive from Medicare. If the claim is denied, the EOB will say why. Common reasons include "not medically necessary" (usually because the medical necessity letter was missing) or "frequency limitation exceeded" (the five-year window has not passed). If you believe the denial is wrong, your doctor can appeal it on your behalf.
What happens if you need a study but five years have not passed
If your doctor believes you need a sleep study but fewer than five years have passed since your last one, ask your doctor to write a detailed note explaining the medical reason. Examples include: a significant change in your symptoms, a new diagnosis, a failed or intolerant treatment that requires reassessment, or a new treatment you want to test. The stronger and more specific the medical reason, the better the chance Medicare will cover it.
Your doctor can submit this note to Medicare for a coverage information before the study is done. This is called a "predetermination" or "prior authorization request." It takes a few weeks, but it tells you in advance whether Medicare will pay. If Medicare says no, you can decide whether to pay out of pocket or wait until five years have passed.
Frequently Asked Questions
Does the five-year rule reset on January 1st?
No. The five-year window is measured from the date of your previous sleep study, not from the calendar year. If your last study was in March 2020, your next covered study would be in March 2025 or later.
Will Medicare cover a home sleep test if I had a lab study five years ago?
Yes, as long as the home test is ordered by your doctor and conducted by a Medicare-certified provider. Home tests and lab studies both count toward the same five-year limit, so a home test now would reset the clock for five more years.
What if my sleep lab is not Medicare-certified?
Medicare will not pay. You can search for certified labs on the Medicare website or ask your doctor for a referral to one. If you use a non-certified lab, you will likely owe the full cost.
Can my doctor appeal if Medicare denies a second study within five years?
Yes. Your doctor can file an appeal with Medicare and include the medical necessity documentation. The appeal process takes several weeks. Ask your doctor's office whether they will handle the appeal or whether you need to submit it yourself.
Do I need prior authorization before a sleep study?
Medicare does not always require it, but your doctor or the lab can request a predetermination to confirm coverage before you have the test. This is especially useful if it is a second study within five years or if you are unsure whether you meet the rules.