CO-110 denial code
Billing date predates service date
How to fix it
Correct the dates and resubmit. Usually a keying or system configuration error.
How to prevent it
Check claim-build date logic where this recurs; it is a system problem rather than a staff one.
In practice
A batch of claims returns CO-110 stating the billing date precedes the date of service. The claims were built on the last day of the month for services delivered on the first of the next.
The error is in claim construction rather than in anything clinical. A claim cannot be billed before the service it describes, and the system produced a date combination that is chronologically impossible.
Correcting the dates and resubmitting clears the individual claims. The more useful response is finding why the build produced them, because a system that can generate this date pairing will generate it again next month.
What sits behind it
The usual mechanisms are recognisable once you look for them. A charge entered in advance of a scheduled service, a template carrying a stale date, a batch process stamping the run date rather than the service date, or a time zone offset shifting a late evening service across midnight.
Recurring instances point at configuration rather than staff. Where the same combination appears repeatedly the fault is in how the claim build assigns dates, and correcting individual claims addresses the symptom while leaving the generator untouched.
This is one of the cheapest denials to eliminate entirely, because the check is pure arithmetic. A scrubber rule rejecting any claim where the billing date precedes the service date costs nothing to build and catches every instance before submission.
Related codes
Terms used here — Clean Claim · Claim Scrubbing · EDI 837
How we handle it — Claims Management · Revenue Cycle Management · Medical Billing & Coding
Primary sources
The rules behind CO-110, at the bodies that publish them.
- Remittance Advice Remark Codes (RARC) (opens in a new tab)
X12 — The remark codes that qualify a CARC on an ERA. Reading the RARC is usually what tells you whether a denial is appealable.
- CMS-1500 claim form standards (opens in a new tab)
National Uniform Claim Committee — Maintainer of the CMS-1500 professional claim form and its data element definitions, plus the provider taxonomy code set.
- NPI Registry (NPPES) (opens in a new tab)
Centers for Medicare & Medicaid Services — Public lookup and management for National Provider Identifiers. A stale NPPES record is a quietly common cause of enrollment and claim rejections.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-110
Charges entered ahead of a scheduled service, templates carrying a stale date, batch processes stamping the run date instead of the service date, and time zone offsets shifting a late evening encounter across midnight. All four are system behaviours rather than staff errors.
Yes, and it is among the simplest rules to build. The check is arithmetic — reject any claim where the billing date is earlier than the service date — and it eliminates the entire category before submission rather than catching it in a denial.
Correct them, but also find the generator. A date combination that is chronologically impossible came from somewhere in the claim build, and fixing only the affected claims leaves the same defect producing the same denial in the next cycle.
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