Which Lab Networks Medicare Accepts and How to Check Before Your Test

Medicare covers both LabCorp and Quest Diagnostics, but only when the test is ordered by your doctor and meets Medicare's medical necessity rules

Both LabCorp and Quest are in-network with Medicare, meaning Medicare will pay its share of the cost when you have a test done at either lab. However, "in-network" does not mean free or that Medicare automatically covers every test. Your doctor must order the test, it must be medically necessary, and you will still owe your deductible, coinsurance, or copay depending on your specific Medicare plan and the type of test.

The real question is not whether Medicare recognizes these labs — it does — but whether your particular test, ordered by your particular doctor, will be covered under Medicare's rules. That depends on what the test is, why your doctor ordered it, and which part of Medicare you are on.

Key Takeaways

Medicare Part B covers lab work ordered by your doctor at both LabCorp and Quest when the test meets Medicare's medical necessity standards.
Your out-of-pocket cost depends on whether you have met your Part B deductible and whether you have a Medigap or Medicare Advantage plan that changes your copay or coinsurance.
Before your test, ask your doctor's office to confirm the test is covered by Medicare and what you will owe out of pocket.
If your doctor orders a test that Medicare does not cover, you can ask to pay out of pocket or request a different test that is covered.

How Medicare Part B Covers Lab Tests at LabCorp and Quest

Medicare Part B is the part of Original Medicare that covers outpatient services, including lab work. When your doctor orders a test at LabCorp or Quest, Medicare Part B will pay 80 percent of the approved amount after you meet your annual deductible. You pay the remaining 20 percent as coinsurance.

This applies to routine tests like blood work, urinalysis, and cholesterol screening when your doctor orders them for a medical reason. The lab itself does not decide whether Medicare covers it — Medicare's rules do. LabCorp and Quest both process Medicare claims the same way any other lab would.

If you have a Medicare Advantage plan (Part C), your coverage works differently. Your plan contract determines what you pay at LabCorp or Quest, and it may be a flat copay instead of 20 percent coinsurance. You should check your plan documents or call your plan's customer service line before your test to learn your exact out-of-pocket cost.

What Tests Medicare Covers and What It Does Not

Medicare covers lab tests that your doctor orders for diagnosis, treatment, or monitoring of a medical condition. Common covered tests include blood glucose screening, cholesterol panels, thyroid function tests, and tests to monitor chronic conditions like diabetes or heart disease.

Medicare does not cover screening tests that are not tied to a symptom or diagnosis. For example, Medicare covers a PSA test for prostate cancer screening once every five years for men 50 and older, but only if your doctor orders it. Medicare does not cover routine wellness bloodwork ordered without a medical reason, even if you ask for it and pay out of pocket upfront — Medicare's rules prevent the lab from billing you for a test Medicare deems not medically necessary.

Some tests fall into a gray area. Genetic testing, advanced imaging-related labs, and certain specialty tests may require prior authorization from Medicare before the lab can process the claim. Your doctor's office usually handles this, but it is worth asking whether your specific test needs approval before you go to the lab.

Your Out-of-Pocket Costs at LabCorp and Quest

If you have Original Medicare (Part A and Part B), your cost depends on whether you have met your Part B deductible for the year. For 2024, the Part B deductible is $240. Once you meet it, you pay 20 percent of the Medicare-approved amount for the lab test.

The Medicare-approved amount is not the same as the lab's full price. LabCorp and Quest both have negotiated rates with Medicare. If the lab's charge is higher than Medicare's approved amount, the lab must write off the difference — you do not pay it. For example, if LabCorp's charge is $100 but Medicare's approved amount is $60, you pay 20 percent of $60 ($12), not 20 percent of $100.

If you have a Medigap policy (supplemental insurance), it may cover some or all of your coinsurance. If you have a Medicare Advantage plan, your copay or coinsurance is set by your plan and may be lower than 20 percent. Always check your plan documents or call your plan before the test.

How to Confirm Coverage Before Your Test

The safest step is to ask your doctor's office to confirm that Medicare covers the test before you go to the lab. Your doctor's staff can often tell you whether the test is covered and what your out-of-pocket cost will be. They may need to know whether you have Original Medicare or a Medicare Advantage plan.

You can also call Medicare directly at 1-800-MEDICARE (1-800-633-4227) and give them the test code (CPT code) and the reason your doctor ordered it. Medicare staff can tell you whether the test is covered and what your cost will be based on your deductible status.

If you call LabCorp or Quest directly, they can tell you what the lab's charge is and whether the test is in-network with Medicare, but they cannot tell you what Medicare will actually pay or what you will owe — that depends on your specific Medicare coverage. Always confirm with your doctor's office or Medicare first.

What to Do If Medicare Does Not Cover Your Test

If your doctor orders a test that Medicare does not cover, you have options. Your doctor can order a different test that Medicare does cover. You can ask to pay out of pocket for the test yourself, though the lab may require you to sign a form stating you understand Medicare will not pay and you are responsible for the full cost.

Some tests that Medicare does not cover are covered by Medicare Advantage plans, so if you have a Medicare Advantage plan, check with your plan before assuming you cannot have the test. If you are on Original Medicare and want a test Medicare does not cover, you can pay the lab's full charge directly, but you should ask the lab for a cost estimate first.

Do not assume that because a test is available at LabCorp or Quest it is covered by Medicare. Always confirm with your doctor or Medicare before going to the lab.

LabCorp Versus Quest: Is There a Difference for Medicare Patients

From Medicare's perspective, LabCorp and Quest are treated the same way. Both are in-network with Medicare, both process Medicare claims, and both must accept Medicare's approved amount as payment in full (after you pay your share). Your out-of-pocket cost for the same test should be the same at either lab.

The practical difference is location and convenience. LabCorp and Quest have different numbers of locations in different areas. Your doctor may send you to one lab or the other based on which is closer to you or which your doctor's office has a relationship with. You can ask your doctor if you have a preference, but Medicare coverage will be the same either way.

Some Medicare Advantage plans may have preferred lab networks, so if you have a Medicare Advantage plan, check your plan documents to see whether one lab has a lower copay than the other. Original Medicare does not have preferred labs — both are treated equally.

Frequently Asked Questions

Do I need a referral to get a lab test at LabCorp or Quest?

No, you do not need a referral. You need an order from your doctor. Your doctor writes an order for the specific test, and you take that order to LabCorp or Quest. The lab will not perform the test without a doctor's order, and Medicare will not pay for it without one.

What if I go to LabCorp or Quest without a doctor's order?

The lab will not perform the test. Both labs require a doctor's order before they will draw blood or process any specimen. If you want to pay out of pocket for a test without a doctor's order, you would need to use a direct-to-consumer lab service, which Medicare does not cover.

Will LabCorp or Quest tell me what Medicare will pay?

The lab can tell you what the lab's charge is and whether the test is in-network with Medicare. They cannot tell you what Medicare will actually approve or what you will owe, because that depends on your deductible status, your specific plan, and Medicare's rules for that particular test. Always ask your doctor's office or call Medicare for that information.

Can I use my Medicare card at LabCorp or Quest?

Yes. Bring your Medicare card and any other insurance cards you have (Medigap or Medicare Advantage) when you go to the lab. The lab will use your Medicare information to submit the claim to Medicare and bill you for your share of the cost.

What if the lab bills me more than my 20 percent coinsurance?

Contact the lab and ask for an explanation. LabCorp and Quest must accept Medicare's approved amount as payment in full. If they bill you more than your coinsurance (20 percent of the approved amount after your deductible), that is a billing error and you should not pay it. You can also file a complaint with Medicare if the lab continues to overcharge.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.