Medicare Denied Lab Work or Diagnostic Test

What This Means

Medicare denied payment for a lab test or diagnostic test because it didn’t meet Medicare’s coverage rules. This is one of the most common types of Medicare denials, and it often comes down to a mismatch between the diagnosis code on the claim and what Medicare requires.

This doesn’t necessarily mean the test wasn’t needed. It may mean the paperwork didn’t support coverage under Medicare’s specific rules.

Why This Happens

• The diagnosis code didn’t match the test. Medicare maintains detailed lists of which diagnosis codes justify each lab test. These lists are called National Coverage Determinations (NCDs) and Local Coverage Determinations (LCDs). If the code on your claim isn’t on the approved list for that test, Medicare denies it automatically.
• The test exceeded a frequency limit. Medicare limits how often certain tests can be performed. For example, some blood tests are covered once per year or once every two years. If your test was ordered sooner than the allowed interval, it may be denied.
• The test was considered screening, not diagnostic. Medicare draws a line between “screening” tests (checking for a disease when you have no symptoms) and “diagnostic” tests (investigating a specific symptom or condition). Some screening tests are only covered on a set schedule or not at all.
• Missing or incomplete documentation. The lab or your doctor’s office may not have submitted enough information to support medical necessity.
• The test isn’t covered by Medicare. Some newer or specialized tests may not yet have a coverage determination, or Medicare may have specifically decided not to cover them.

Should You Appeal?

What To Do Next

1. Check whether you signed an ABN. If your provider gave you an Advance Beneficiary Notice before the test and you signed it, you may be financially responsible. If you did not receive an ABN, the lab generally cannot bill you for a denied test.
2. Contact your doctor’s office first. Ask them to review the diagnosis code on the claim. If a more specific or accurate code applies, they may be able to resubmit the claim without a formal appeal.
3. Review your denial notice. Your Medicare Summary Notice (MSN) or Explanation of Benefits (EOB) will indicate the reason for the denial. Look for references to medical necessity, coverage criteria, or frequency limits.
4. If resubmission doesn’t work, file an appeal. Ask your doctor for a letter explaining why the test was medically necessary for your condition. Include this with your appeal along with any relevant medical records.
5. Check the LCD or NCD for your test. You can look up coverage rules in the CMS Medicare Coverage Database. This can help you understand what Medicare requires and whether your situation qualifies.
6. Get free help. Contact your State Health Insurance Assistance Program (SHIP) or call 1-800-MEDICARE (1-800-633-4227).

Sources

• Medicare.gov: Diagnostic Laboratory Tests
• CMS: Medicare Coverage Database — NCDs and LCDs
• CMS: Medicare Coverage Determination Process
• CMS: Local Coverage Determinations

Frequently Asked Questions