Federal Law & QMB: Why Your Practice Cannot Bill Medicare Patients for Copays or Deductibles

If your dental practice is billing medical insurance for sleep medicine, oral surgery, or other medically necessary procedures, there is a federal law you need to know cold. Violating it can result in civil monetary penalties, mandatory refunds, and in serious cases, exclusion from Medicare and Medicaid.

The law protects a group of patients known as Qualified Medicare Beneficiaries (QMBs). These are low-income Medicare patients who also qualify for a Medicaid program that covers their Medicare cost-sharing, including deductibles, coinsurance, and copayments. Federal law does not just discourage billing them for these amounts. It prohibits it entirely.

What Is the QMB Program?

The Qualified Medicare Beneficiary (QMB) program is one of four Medicare Savings Programs (MSPs) administered by state Medicaid agencies. It is designed to assist low-income Medicare beneficiaries with their Medicare costs.

In 2026, QMB income limits are $1,350/month for individuals and $1,824/month for married couples. Beneficiaries who qualify receive:

• Payment of Medicare Part A and Part B premiums
• Coverage of Medicare deductibles
• Coverage of Medicare coinsurance and copayments

For billing purposes, QMB patients have Medicare as primary and Medicaid as secondary. Approximately 7.4 million Medicare beneficiaries are enrolled in the QMB program. Many of them visit dental practices that bill medical insurance.

The Federal Law: What It Says

Additional statutory authority comes from Sections 1866(a)(1)(A) and 1848(g)(3)(A) of the Social Security Act, which make the billing prohibition a condition of the Medicare Provider Agreement. In other words, the moment you signed up to accept Medicare, you agreed to follow this rule.

CMS has issued explicit guidance reinforcing this prohibition, including MLN Matters articles and reminder memos directed at all Medicare providers and suppliers. The prohibition is not a gray area. It is clear, enforceable federal law.

Who This Applies To

This is one of the most commonly misunderstood aspects of QMB billing: the prohibition applies to all Medicare providers, whether or not they participate in Medicaid.

Many dental practices assume that because they do not accept Medicaid, they are free to bill QMB patients for their Medicare cost-sharing. This is incorrect. The law does not condition the billing prohibition on Medicaid participation. If you accept Medicare, you must comply.

The prohibition also extends to:

• Medicare Advantage (Part C) plans
• Medicare Part D prescription drug plans (for pharmacies)
• All Medicare-covered items and services
• Any Medicare cost-sharing amount, including annual deductibles, per-visit copayments, and coinsurance percentages

How Billing Should Work for a QMB Patient

When you have a patient with QMB status, the correct billing sequence is straightforward:

1. 1
   Verify QMB Status Before the Appointment

   Run an eligibility verification (270/271 EDI transaction) prior to the visit. QMB enrollment should appear in the eligibility response. You can also call 1-800-MEDICARE or check with your state Medicaid agency.

2. 2
   Submit the Claim to Medicare First

   Bill Medicare as the primary payer as you normally would. Submit your claim with the appropriate procedure codes, diagnosis codes, and provider information.

3. 3
   Crossover to Medicaid Automatically

   In most cases, Medicare will automatically crossover the claim to the state Medicaid agency after processing. Medicaid will then pay some or all of the cost-sharing amount, up to the Medicaid fee schedule rate, for those practices enrolled in Medicaid. If you are not enrolled in Medicaid, Medicaid will pay $0.

4. 4
   Accept Combined Payment as Payment in Full

   Whatever Medicare pays plus whatever Medicaid pays (if anything) is your total payment. You must accept this combined amount as payment in full. You cannot bill the patient for any remaining balance, even if Medicaid pays nothing.

5. 5
   Do Not Collect a Copay at the Time of Service

   Do not collect copays or cost-sharing at check-in or checkout from QMB patients. If staff collect a copay from a QMB patient out of habit, it must be refunded immediately.

What Happens If Medicaid Does Not Pay the Full Cost-Sharing?

This is where many practices get frustrated, and understandably so. In some states, Medicaid reimburses providers for the full Medicare cost-sharing amount. In others, Medicaid pays nothing beyond the Medicare payment (because the Medicare payment already equals or exceeds the Medicaid fee schedule rate).

In the latter scenario, your practice absorbs the cost-sharing amount as a contractual write-off. This is not optional. Federal law is explicit: the billing prohibition holds even when Medicaid does not reimburse the cost-sharing. The patient still owes nothing.

This is why verifying QMB status before rendering services is so important. Knowing ahead of time allows your billing team to code and document the encounter correctly and set the right payment expectations internally.

Penalties for Improper Billing

Providers who bill QMB patients for Medicare cost-sharing are in violation of their Medicare Provider Agreement. CMS takes this seriously. Consequences include:

• Civil monetary penalties imposed by the Office of Inspector General (OIG)
• Mandatory refunds of all improperly collected cost-sharing amounts
• Exclusion from Medicare and Medicaid in severe or repeated cases
• Termination of the Medicare Provider Agreement

The OIG actively investigates complaints about improper QMB billing. Beneficiaries and advocacy organizations frequently file complaints, and CMS has issued multiple enforcement reminders to providers across all specialties.

Why This Matters for Dental Practices Billing Medical Insurance

Dental practices billing medical insurance are increasingly encountering QMB patients, particularly those treating conditions related to sleep medicine, oral surgery, or medically necessary dental procedures. These are often older, lower-income patients, exactly the demographic the QMB program serves.

The problem is that most dental billing workflows are built around dental insurance, where patients routinely pay a copay or percentage at checkout. When the same front-desk team handles medical insurance claims without QMB training, the habit of collecting a copay can carry over, creating an inadvertent but serious compliance violation.

Building QMB screening into your eligibility verification process, combined with clear staff protocols, eliminates the risk. Eligibility verification through a proper clearinghouse will flag QMB status in the 271 response, giving your team the information they need before the patient arrives.

Key Takeaways

• QMB patients have Medicare as primary and Medicaid as secondary
• Federal law (Social Security Act §1902(n)(3)(B)) prohibits billing QMB patients for any Medicare cost-sharing
• The prohibition applies to all Medicare providers, whether or not you accept Medicaid
• Bill Medicare first, crossover to Medicaid, and accept the combined payment as payment in full
• Do not collect copays at check-in or checkout from QMB patients
• Verify QMB status through eligibility verification (270/271) before every appointment
• Violations can result in civil monetary penalties, mandatory refunds, and exclusion from Medicare