How to read a Medicare denial letter

The letter is written by a system for a system. It uses words like “not medically necessary” to mean “the doctor’s note did not include the phrase we look for”, and it puts the deadline in a paragraph most people never reach. Reading it correctly is a skill, and this guide teaches it.

Many “denials” are not. A provider’s bill sent before Medicare finished processing looks like a denial and is not. A claim denied because it was sent to Medicare when a Medicare Advantage plan is primary is a routing error. A claim marked as the patient’s responsibility because the deductible had not been met is not a denial. Compare the provider’s bill with the MSN or plan statement before concluding anything.

On an MSN, each denied line has a footnote or remark code explained on the back or a following page. On a plan letter, the reason is stated, sometimes in a sentence, sometimes by reference to a policy. The reasons fall into recognisable families:

• Documentation: “information needed from your provider”, “documentation does not support”, “not medically necessary as documented”. This is the most common, and it means the doctor’s office needs to send or correct something. Resubmission usually fixes it.
• Coding: wrong procedure code, wrong diagnosis code, a code combination Medicare does not accept. The provider corrects and resubmits.
• Eligibility or enrollment: the supplier is not enrolled, the provider is out of network, the patient was not enrolled in that Part on the date of service.
• Frequency or duplicate: the service was billed more often than allowed, or twice. Often a billing error.
• Coverage: the service is statutorily excluded (routine dental, hearing aids, custodial care) or does not meet a national or local coverage determination. These are real denials and appeals succeed only with strong medical justification.
• Prior authorization: for Medicare Advantage, the service required approval that was not obtained. Sometimes fixable retroactively; often the basis of appeal.
• Timely filing: the claim was submitted too late. The provider’s problem, and generally the patient cannot be billed for it.

For an Original Medicare first-level appeal, Medicare says 120 days after getting the MSN; follow the deadline shown on it. For a first-level Medicare Advantage or Part D appeal, Medicare says 65 days from the initial denial notice. Request expedited review when the applicable health-risk criteria are met. Record the deadline, and do not assume a provider’s resubmission pauses it.

1. 1.If it is a documentation or coding issue: call the provider’s billing office, tell them the reason code, and ask them to correct and resubmit. Most denials end here.
2. 2.If it is a routing or eligibility error: tell the provider which insurance was primary on that date and ask them to rebill.
3. 3.If it is a real coverage denial you believe is wrong: appeal. Our appeals guide walks through the levels. Get the doctor’s office to write a letter of medical necessity addressing the specific reason.
4. 4.If it is a statutory exclusion: appeals rarely succeed. Look for other funding.
5. 5.If a bill arrives for a denied service: do not pay until the denial is understood and the resubmission or appeal has run. Tell the provider in writing that the claim is under review.

The letter, the MSN, the provider bills, notes of every call with the date and the name of the person. Denials that go to appeal are won on paper trails. Medicare.gov’s online account shows claims as they process and is faster than waiting for a paper notice; set one up for your parent with their permission.