CO-200 denial code
Expenses incurred during a lapse in coverage
How to fix it
Confirm the lapse dates. Where coverage was reinstated retroactively, resubmit after reinstatement.
How to prevent it
Grace-period status is visible at verification for exchange plans; check it rather than assuming active means paid.
In practice
A patient on a marketplace plan misses two months of premium payments. Services delivered during the second month return CO-200, because the date fell inside a grace period lapse.
The plan is not terminated and the patient may not know anything is wrong. Coverage is suspended pending payment, and claims incurred during the suspension are held rather than paid.
These denials are frequently reversible. If the patient pays the outstanding premium within the grace period, coverage is reinstated retroactively and the claim becomes payable, so this is one to hold rather than write off.
What sits behind it
Subsidised marketplace enrolees have a mandated three-month grace period, and the structure matters. Claims from the first month are generally paid; claims from the second and third are held pending payment and denied if the premium is never brought current.
That structure creates a specific risk for providers. Services delivered in months two and three may ultimately go unpaid, and eligibility responses during the period often still show active coverage, so the exposure is invisible at the point of care.
The check that surfaces it is reading grace period status in the eligibility response rather than the active flag. Where that status is available, a practice can know before the visit that payment is uncertain and handle it with the patient rather than after.
Related codes
Terms used here — Eligibility Verification · Patient Responsibility · Denial
How we handle it — Eligibility Verification · Patient Collections · Denial Management
Primary sources
The rules behind CO-200, at the bodies that publish them.
- Medicare Secondary Payer Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — When Medicare pays second, and to whom the claim goes first. Coordination-of-benefits denials are resolved here rather than with the patient.
- 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.
- Claim Adjustment Reason Codes (CARC) (opens in a new tab)
X12 — The authoritative, maintained CARC list. Our denial code lookup explains these in plain English; X12 is where the canonical definitions live.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-200
Frequently. If the patient brings the premium current within the grace period, coverage is reinstated retroactively and claims from the suspended months become payable. Holding these for recheck rather than writing them off recovers real money.
For subsidised marketplace enrolees, claims from the first month are generally paid while claims from the second and third are held pending payment. If the premium is never brought current, the held claims are denied and coverage terminates retroactively.
Often yes, if you read the eligibility response fully rather than stopping at the active flag. Many responses carry grace period indicators, which lets the practice know that payment is uncertain before care is delivered rather than months afterwards.
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