CO-35 denial code
Lifetime benefit maximum has been reached
How to fix it
Confirm the maximum genuinely applies to this benefit category, then look for secondary coverage.
How to prevent it
Where a plan carries lifetime maxima, track accumulated benefit for affected patients rather than discovering it at denial.
In practice
A patient with a long history of infertility treatment attends for a further cycle. The claim returns CO-35 — the plan carries a lifetime maximum for that benefit category and it has been reached.
Lifetime maxima survive plan years. Unlike an annual deductible that resets each January, the accumulator carries forward across every year the patient has held the coverage, and in some designs across predecessor plans from the same employer.
Confirm the maximum genuinely applies to the benefit category billed, since accumulators are frequently mis-assigned. Then look for secondary coverage, because a second plan with its own untouched maximum can cover what the first no longer will.
What sits behind it
The legal landscape here is narrower than it once was. The Affordable Care Act prohibits lifetime dollar limits on essential health benefits, so a lifetime maximum on a genuinely essential service is worth challenging rather than accepting. What remains lawful are limits on non-essential benefits and limits expressed in units rather than dollars.
That distinction is where most successful appeals live. A plan capping infertility treatment or adult dental care is generally within its rights. A plan capping hospital care or prescription drugs in dollars is not, and identifying which category the denied service falls into determines whether an appeal has anything to work with.
Category-specific maxima are handled under CO-149 rather than here, and the difference matters when tracking accumulators. Practices delivering long courses of capped care serve patients better by monitoring the remaining benefit and warning them before exhaustion than by discovering it at the point of denial.
Related codes
Terms used here — Patient Responsibility · Eligibility Verification · Appeal
How we handle it — Eligibility Verification · Denial Management · Patient Support
Primary sources
The rules behind CO-35, at the bodies that publish them.
- Medicare Coverage Database (LCD/NCD) (opens in a new tab)
Centers for Medicare & Medicaid Services — Searchable national and local coverage determinations. The direct answer to whether a diagnosis supports medical necessity for a given procedure.
- Medicare Benefit Policy Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — What Medicare covers and under what conditions, as distinct from how a claim is processed. The starting point for any coverage or medical necessity question.
- Advance Beneficiary Notice of Noncoverage (ABN) (opens in a new tab)
Centers for Medicare & Medicaid Services — The form and the rules for issuing it. Whether a non-covered service can be billed to the patient usually turns on whether a valid ABN was obtained beforehand.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-35
Only in limited form. The Affordable Care Act bars lifetime dollar limits on essential health benefits, so a dollar cap applied to hospital care, prescription drugs or maternity services is challengeable. Caps on non-essential benefits such as infertility treatment or adult dental, and caps expressed in visits rather than dollars, remain lawful.
No, that is what distinguishes it from an annual limit. The accumulator carries across plan years for as long as the patient holds the coverage, and some employer designs carry it across predecessor plans too. Only a genuinely new plan starts a fresh accumulator.
Check for secondary coverage with its own untouched limit, verify the accumulator was applied to the right benefit category, and confirm the cap is lawful for the service. If all three fail, the balance becomes the patient's, and telling them before the next service is delivered is the useful step.
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