Qualified Medicare Beneficiary (QMB) Billing: What You Can't Collect and How to Spot QMB Status

Updated November 9, 2026, based on CMS, the Social Security Act and CMS's HETS 270/271 guidance as of that date.

A Qualified Medicare Beneficiary (QMB) is a Medicare patient whose state Medicaid program pays their Medicare premiums and cost sharing. Federal law bars every Medicare provider, whether or not it takes Medicaid, from billing a QMB for Part A or Part B deductibles, coinsurance or copays, even when Medicaid pays nothing toward them.

Missing QMB status on an eligibility check is costly. If the front desk collects a copay or a deductible balance goes to collections, the practice has to recall the bill and refund the money. CMS's QMB program page puts the group at more than 8 million people in 2023, over 1 in 8 Medicare beneficiaries.

What the QMB billing prohibition covers

The rule comes from section 1902(n)(3)(B) of the Social Security Act, codified at 42 U.S.C. 1396a(n)(3)(B). When a state reduces or skips its payment of Medicare cost sharing for a QMB, the Medicare payment plus any Medicaid payment counts as payment in full, and the beneficiary "shall not have any legal liability to make payment to a provider" for the service.

CMS's MLN fact sheet on the prohibition on billing QMBs spells out the practical scope:

• It applies to all Original Medicare and Medicare Advantage providers and suppliers, including pharmacies, not only those that accept Medicaid.
• It covers Part A and Part B deductibles, coinsurance and copayments for covered items and services.
• It applies on every date of service on which the patient is a QMB.
• It holds even if the patient's QMB benefit comes from a different state than the one where they get care.
• A QMB can't choose to pay the cost sharing to keep the relationship smooth.

Billing a QMB violates the Medicare provider agreement or Part C obligations and can lead to sanctions. CMS's July 2018 QMB billing FAQ adds that the rule covers Part B-covered drugs, while pharmacies may still collect the Low Income Subsidy copays on Part D drugs.

QMB vs SLMB and QI: which programs pay cost sharing

QMB is one of the Medicare Savings Programs (MSPs). They all run through state Medicaid, but only QMB covers cost sharing. CMS's fact sheet on beneficiaries dually eligible for Medicare and Medicaid summarizes them:

• QMB: covers Part A and Part B premiums, deductibles, coinsurance and copayments. Federal floor is income up to 100% of the federal poverty level.
• SLMB (Specified Low-Income Medicare Beneficiary): covers only the Part B premium. Income between 100% and 120% of FPL.
• QI (Qualifying Individual): covers only the Part B premium, for income between 120% and 135% of FPL. A QI can't have any other Medicaid eligibility.
• QDWI (Qualified Disabled Working Individual): covers only the Part A premium for certain people under 65 with disabilities who lost premium-free Part A after returning to work.

Each of QMB and SLMB has a "plus" version for people who also qualify for full Medicaid. CMS's dual eligibility categories document assigns codes: QMB-only is 01, QMB Plus is 02, SLMB-only 03, SLMB Plus 04, QDWI 05, QI 06, and other full-benefit duals 08. States can raise the income and resource limits above the federal floor (except for QDWI), and CMS updates the dollar figures every year.

An SLMB-only or QI patient gets Medicaid help with a premium only, so the QMB prohibition doesn't apply to their cost sharing. An SLMB Plus or other full-benefit dual may still be protected under their Medicaid coverage, which the companion guide on dual eligibles and D-SNPs covers.

How to tell a patient is QMB on an eligibility check

The MLN QMB fact sheet names your Medicare Administrative Contractor's provider portal, your clearinghouse or vendor's HETS-based eligibility check, the Medicare remittance and Medicare Summary Notice, the state's Medicaid eligibility system, and the patient's Medicaid card or other state proof.

On a Medicare 270/271, CMS's HETS 270/271 companion guide (section 7.21, QMB Period Business Rules) says the 271 returns QMB periods in a 2110C loop with EB04 = "QM". An enrollment period looks like this:

• `EB*R***QM*State QMB Plan~`, where EB05 is the state code plus "QMB Plan"
• `DTP290...`, with D8 if the QMB period is ongoing and RD8 if it has an end date

QMB financials come back in separate 2110C EB segments, also with EB04 = "QM", such as a Part A deductible of zero for dates inside the QMB period. Your clearinghouse may show this as a QMB flag or a "Medicaid/QMB" line rather than raw segments, so ask how its screen displays it.

The same guide sets three limits:

1. QMB periods only return when they overlap a calendar year in the request dates, a benefit period (spell) the 271 returns, or the current date. A 271 run for the wrong dates can miss one.
2. QMB status "may fluctuate for a small percentage of Beneficiaries." If HETS shows the QMB period ended, CMS says to verify through the state's online Medicaid eligibility system or state-issued documents.
3. CMS directs QMB eligibility questions to the state Medicaid system, not the MAC.

For Medicare Advantage patients, HETS shows the MA plan, and CMS tells providers to contact the plan to learn how it shows QMB status before and after claims. CMS's October 2024 reminder memo to MA plans encourages plans to put QMB status on member ID cards, provider portals and Explanations of Benefits. Plans see dual status codes 01 and 02 for QMBs in their monthly CMS files.

In practice, run the Medicare check first, then the state Medicaid check whenever HETS or the plan shows Medicaid involvement or a QMB end date. The state check tells you the aid category and whether the patient is QMB-only or QMB Plus. Our guide to what a 271 eligibility response leaves out covers when a portal check is worth the extra time.

How QMB status shows on the Medicare remittance

For Original Medicare claims, the Medicare Claims Processing Manual, chapter 1, section 200 describes what the claims system sends. When the date of service falls in a QMB period (or the discharge date, for inpatient claims), the 835 remittance still shows deductible and coinsurance amounts under group code PR with CARC 1, 2 or 66, plus one of two alert remark codes:

• N781: Patient is a Medicaid/Qualified Medicare Beneficiary. Review your records for any wrongfully collected deductible. This amount may be billed to subsequent payer.
• N782: the same alert for coinsurance.

On most claims, PR means the balance goes to the patient. On a line with N781 or N782, it goes to the state or gets written off. Set posting rules so these lines don't land on patient statements. The patient's Medicare Summary Notice shows $0 in "Maximum You May Be Billed" for paid QMB lines.

Billing the state for QMB cost sharing

You can bill the state Medicaid program for the cost sharing, but you may not get it all. Under 42 U.S.C. 1396a(n)(1) and (2), a state doesn't have to pay cost sharing beyond what its Medicaid rate would have paid for the service. Under this "lesser-of" approach, if Medicare already paid more than the Medicaid rate, the state can pay zero. The patient still owes nothing.

From the MLN QMB fact sheet:

• Nearly all states, and many Medicaid managed care plans, receive Original Medicare claims through the electronic crossover. The Medicare remittance notes when a claim crossed over.
• States must let Medicare-enrolled providers enroll for the purpose of billing QMB cost sharing, even if the provider type isn't in the state plan.
• Certain provider types can claim unpaid QMB cost sharing as Medicare bad debt, but only after billing the state and receiving a Medicaid remittance (see 42 CFR 413.89).

If a claim didn't cross over, check the state's enrollment and the patient's Medicaid ID before rebilling. For Medicare Advantage claims, ask the plan and the state how the cost sharing is billed. It varies.

When a QMB can be charged something

The exceptions are narrow, per the dual eligibility fact sheet, CMS's July 2018 QMB billing FAQ and the statute:

• A small Medicaid copay set by the state, where one applies.
• Services Medicare denies or never covers. The prohibition covers Medicare cost sharing on covered services. Even with a valid ABN, you can't bill a dual eligible up front. After Medicare and Medicaid adjudicate, a QMB-only patient may be liable if Medicare denies the claim; a patient with full Medicaid may be liable only if Medicaid also denies, subject to state law. For services Medicare excludes by statute, the FAQ says a QMB-only patient can be billed, while a patient with full Medicaid can be billed only if Medicaid won't cover the service, subject to state law.
• Secondary coverage. The statute doesn't stop a Medigap policy or employer retiree plan from paying Medicare cost sharing on the patient's behalf.
• Part D drugs. Pharmacies may collect Low Income Subsidy copays.

What to do if you've already billed a QMB

The MLN QMB fact sheet says to recall any bill for QMB Medicare cost sharing, including bills turned over to collections, and refund anything collected. Then fix the cause: add the state Medicaid check to intake for Medicare patients with Medicaid, flag N781 and N782 lines in posting, and check whether your clearinghouse surfaces the HETS QMB period. Because status can change, recheck at each visit; see how often to verify insurance eligibility.

Frequently asked questions

Does the QMB billing prohibition apply if we don't accept Medicaid?

Yes. CMS says it applies to all Original Medicare and Medicare Advantage providers and suppliers, not only those enrolled in Medicaid. You can still enroll with the state just to bill QMB cost sharing.

What is the difference between QMB and SLMB?

QMB pays Medicare premiums and Part A and B cost sharing, and the patient can't be billed for that cost sharing. SLMB pays only the Part B premium, so an SLMB-only patient's Medicare deductibles and coinsurance follow normal Medicare rules.

What is QMB Plus?

QMB Plus (dual status code 02) is a QMB who also has full Medicaid benefits. QMB-only (code 01) has Medicaid help with Medicare costs but no other Medicaid coverage. Both are protected from Medicare cost sharing.

Does QMB status apply to Medicare Advantage patients?

Yes. The protection covers QMBs in Medicare Advantage plans. Ask each plan how it shows QMB status in its portal, ID card and remittance.

How long does QMB status last?

It lasts while the state keeps the patient in the QMB group, and CMS notes that status can fluctuate. HETS returns QMB start and end dates, and CMS says to confirm an ended period with the state Medicaid system.

Checking QMB status across Medicare and state Medicaid portals?

Champ automates portal work like eligibility checks across payer portals, including Medicaid plan portals. We set it up and run it, so your staff sees only the finished results. If QMB and Medicaid checks are adding time to every Medicare visit, learn more here.

This post is general information, not legal, compliance or billing advice. Rules vary by state and Medicare Advantage plan and change often, so confirm with your Medicare Administrative Contractor, state Medicaid agency or the patient's plan before acting. Champ is not affiliated with or endorsed by CMS or any state Medicaid program.