Can your Medicare contractor just say it's "not medically necessary" with no further explanation?

The denial notice has to explain the basis for the decision and tell you how to appeal. If it doesn't point to a specific rule or criteria, that's itself worth raising in your appeal — you're entitled to know what standard was applied.

What if I don't have all the evidence listed above?

Include what you have. An appeal with partial evidence and a clear explanation of the rule still gets a real review — it doesn't need to be complete to be worth filing.

Original Medicare denied a lab or imaging test as too frequent? What the rule says and how to appeal.

Checked against the current rules on September 23, 2026.

A denial for a lab or imaging test as too frequent isn't the end of the story — Original Medicare has to follow specific coverage rules, and a denial that doesn't square with those rules is exactly the kind of appeal that tends to win.

Here's what the rule actually requires, what evidence usually turns a denial around, and the deadline you're working against.

What the rule requires

A lab or imaging test as too frequent denials like this one turn on your own specific facts and documentation, not a single cited rule — the questions and evidence below are what actually decide it.

Questions that decide it

Before you appeal, these are the facts that usually decide whether a denial like this holds up:

Was there a specific medical reason for repeating this test or service sooner than the usual interval?
Did something change since the last time this test or service was done — new symptoms, an abnormal result, or a change in treatment?

What a winning appeal has to show

An appeal that wins usually includes:

Documentation of the specific medical reason for the earlier-than-usual repeat service — A frequency-limit denial usually turns on whether the documentation explains why this specific instance fell outside the normal interval. (Your doctor's office provides this.)
The date and result of the prior instance of this same test or service — Showing exactly how much time passed, and what changed since the prior instance, directly addresses why the usual interval didn't apply here. (You or your family provide this.)

Your deadline to appeal

120 days from the date on the Medicare Summary Notice — 120 calendar days from when you receive it (42 CFR § 405.942(a)), with receipt presumed to be 5 days after the notice's own date unless shown otherwise.42 CFR 405.942

Your Medicare contractor itself then has its own clock to decide. 60 calendar days from when the MAC receives your timely request. Each time you submit new evidence after filing, that 60-day clock is extended by up to 14 more calendar days for that submission (42 CFR § 405.950(a), (b)(3)) — this can happen more than once.

What to ask your doctor to address

If you're asking the treating physician for a supporting letter, it should speak to:

The specific clinical reason this test or service needed to be repeated sooner than the usual interval.

Questions people ask

Can your Medicare contractor just say it's "not medically necessary" with no further explanation?: The denial notice has to explain the basis for the decision and tell you how to appeal. If it doesn't point to a specific rule or criteria, that's itself worth raising in your appeal — you're entitled to know what standard was applied.
What if I don't have all the evidence listed above?: Include what you have. An appeal with partial evidence and a clear explanation of the rule still gets a real review — it doesn't need to be complete to be worth filing.

Sources — last checked September 23, 2026

42 CFR 405.942as of September 23, 2026

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By CaseWhy Appeals editorial. See how this content is produced. Not legal advice. Not affiliated with or endorsed by Medicare, CMS, or any health plan. A product of CaseWhy LLC.