CARC 167: diagnosis not covered.

What X12 says CARC 167 means

This (these) diagnosis(es) is (are) not covered.

CARC 167 · Start 06/30/2005, last modified 07/01/2017.

X12 usage note: refer to the 835 Healthcare Policy Identification Segment (loop 2110 Service Payment Information REF), if present.

Remark codes that often accompany it

X12 does not publish fixed CARC-to-RARC pairings, so use the remark on your remittance. Relevant remarks include N115 ("This decision was based on a Local Coverage Determination (LCD)"), N386 ("This decision was based on a National Coverage Determination (NCD)"), M76 ("Missing/incomplete/invalid diagnosis or condition") and M64 ("Missing/incomplete/invalid other diagnosis"). The first two tell you which policy to read. The last two say the problem may be the diagnosis data itself, not coverage.

Where the covered diagnosis list lives

For Original Medicare, NCDs and LCDs are published in the CMS Medicare Coverage Database. Policies and their associated articles commonly list the ICD-10-CM codes that support medical necessity. Other payers publish the equivalent in their medical policy. A code absent from the list is what produces a CARC 167.

What to check

• Find the policy named by the remark and read its diagnosis list for the procedure code you billed.
• Check the diagnosis code you billed in the ICD-10-CM search. Was it coded to the highest level of specificity the record supports, and does the code exist for the date of service?
• Check the diagnosis pointer on the line. A supporting diagnosis that is on the claim but not pointed to the service can still produce this denial.
• Check the record. Does the documentation support a diagnosis that the policy does cover? Code what the record supports. Do not choose a code because it is on the covered list.
• If the diagnosis is not on the list and the record supports it, check the policy for a documented exception or an appeal route.

Correct or appeal?

If the diagnosis was coded or pointed wrongly, correct the claim. A processed Medicare claim can be reopened to fix an error within 1 year for any reason (42 CFR 405.980(c)). If the diagnosis is right and simply not covered, the appeal has to argue from the policy's wording and the clinical record. Under 42 CFR 411.15(k)(1) Medicare covers services reasonable and necessary for the diagnosis or treatment of illness or injury, which is the standard a policy applies.

Deadlines for Original Medicare

• Filing the claim: for services on or after January 1, 2010, no later than the close of the period ending 1 calendar year after the date of service (42 CFR 424.44(a)(1)), subject to the exceptions in that section.
• Redetermination: 120 calendar days from receipt of the initial determination, with receipt presumed 5 days after the notice date unless there is evidence to the contrary (42 CFR 405.942). Good cause can extend it.
• Reconsideration: 180 calendar days from receipt of the redetermination notice (405.962).
• ALJ hearing: 60 calendar days from receipt of the reconsideration notice, plus the amount-in-controversy requirement (405.1002).
• Reopening to fix an error: a party may ask the contractor to reopen within 1 year of the determination for any reason, or within 4 years for good cause (405.980(c)).

Medicare Advantage plans and commercial payers set their own deadlines. They are printed on the denial notice or in your contract, and they are often shorter. The calculator on this page covers Original Medicare only.

Worked example (hypothetical)

A claim lists two diagnoses, a covered one and an unrelated one. The service line points only to the second, and the payer denies the line with CO-167 and remark N115. The covered diagnosis was on the claim but not pointed to the line. A corrected claim with the right pointer is the fix. In a different case the only diagnosis in the record is not on the policy's list: the line was properly denied, and the patient's liability turns on the notice given before the service.

Sources

• X12: Claim Adjustment Reason Codes — code text, start and last-modified dates (list dated 10/30/2026, retrieved 2026-11-02)
• X12: Remittance Advice Remark Codes — remark text and dates (retrieved 2026-11-02)
• CMS: Medicare Coverage Database — where NCDs, LCDs and coding articles are published (retrieved 2026-11-02)
• eCFR: 42 CFR 411.15 (particular services excluded from coverage) — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02
• eCFR: 42 CFR 405.980 — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02
• eCFR: 42 CFR 405.942 — regulation text as of the eCFR issue dated 2026-10-29, retrieved 2026-11-02

Every code description and rule above was retrieved from these pages on November 2, 2026. X12 code text is copyrighted by X12 and quoted only for the codes explained here; the complete lists are at x12.org. Payers revise code lists, contracts and policies, so confirm anything that affects a claim or a deadline with the payer.