CO-13 Denial Code: Date of Death Precedes Date of Service

CO-13 is Claim Adjustment Reason Code 13 with group code CO. CARC 13 means the date of death precedes the date of service. A date-of-death edit is a payer check that compares the death date on the patient’s record with the service date on the claim. The payer’s records show the patient died before the day the claim says the service happened. Many people search for “co 13 denial code”, and that is the phrase this page answers. (Primary sources: X12 Claim Adjustment Reason Codes · CMS Claims Processing Manual, Ch. 22, §60.1 · HHS OIG report A-07-16-05089)

Quick answer: CO-13 is a date check, not a coverage decision. Compare the date of service on the claim with the date of death the payer holds. If you keyed the wrong service date or picked the wrong patient, fix the claim and resubmit. If the payer’s death date is wrong, the record has to be corrected at the source before an appeal can work.

Part of our denial codes library. Written by Manikandan, a revenue cycle management specialist with more than 10 years of US medical billing experience. Last reviewed: 16 October 2026. Official code wording is quoted word for word from X12; Medicare rules link to their CMS or Medicare contractor source.

CO-13 denial code description (official X12 wording)

X12 Claim Adjustment Reason Code 13, verbatim:

“The date of death precedes the date of service.”

Source: X12 Claim Adjustment Reason Codes, checked 16 October 2026. Start: 01/01/1995. X12 shows no usage note and no later modification for this code.

The CARC is 13. The group code is usually CO. CMS says CO adjustments are “generally… considered a write off for the provider and are not billed to the patient.” CMS Transmittal 470 (2005) lists reason code 13 with group code CO for Medicare fiscal intermediaries.

What CO-13 means in plain English

• The payer holds a date of death for this patient. It is earlier than the service date on your claim.
• The claim cannot be paid as submitted. Something is wrong with the service date, the patient match, or the death date on file.
• It is a data problem first, because the payer is comparing two dates and not judging the care. It is not a statement that the plan excludes the benefit.
• The family does not get this bill, since the CO group points to a provider-side fix and not to the patient or the estate.
• Same-day cases need care. “Precedes” means earlier than. A service on the day of death needs its own review.

CO-13 vs CO-14, CO-31, CO-27 and lookalikes

Code	Official X12 idea	What it tells you
CO-13	Date of death precedes the date of service	Death date vs service date. This page
14	Date of birth follows the date of service	The date-of-birth version of the same check
31	Patient cannot be identified as our insured	Member match failed. See CO-31
27	Expenses incurred after coverage terminated	Coverage ended. See CO-27
16	Claim/service lacks information or has submission/billing error(s)	Missing or bad data. See CO-16

How the payer reaches CO-13

The payer stores a date of death in the member or beneficiary record. When a claim arrives, the system compares that date with the service date. For Medicare, a 2016 HHS OIG audit says CMS “had procedures that required Medicare contractors to automatically reject any claim that was submitted for payment with a date of service that was after the date of death on record for the beneficiary on the claim.”

Because the information is stored in eligibility and registration systems, the investigation usually begins with verification of identity and documentation of the actual date of service. So the edit is mechanical, because it does not read the chart and it trusts the date on file and the date on the claim, which means that a mistake in either one will trigger it. Other payers may run their own version of the same check.

Common triggers for CO-13

1. Typo in the service date. For example, the year was keyed as 2026 when the visit really took place in 2025.
2. Wrong patient on the claim. A similar name or a shared subscriber ID pulled in another person’s record.
3. Wrong date of death on file. The payer loaded a bad date from its own source, and only the payer or that source can fix it.
4. Billing continued after death. Consider a recurring supply order or monthly rental that nobody stopped when the practice learned of the death.
5. Service on the date of death. The patient was alive at the visit, and the payer’s date is the same day. This case needs documentation.

Where CO-13 shows up in the 835

CLP*PCN71355*4*120.00*0.00*0.00*12*CLAIM881900~
SVC*HC:99213*120.00*0.00**1~
DTM*472*20260312~
CAS*CO*13*120.00~

• Status code 4 means the claim was denied.
• The line paid $0.
• CAS*CO*13*120.00 took the full charge as a date-of-death adjustment.
• The DTM line shows the service date the payer read.
• This sample is illustrative only. Real remits vary.

How to fix CO-13: decision path

1. Confirm the CAS segment. Check the group (CO), the reason (13), and the amount. Save the remit.
2. Check the service date against the schedule, the chart note, and the charge entry.
3. Check the patient. Match name, date of birth and member ID to the person who was seen.
4. Check eligibility. Medicare contractors such as Noridian show the date of death on the eligibility response.
5. If the service date was wrong, correct it and resubmit as a new or corrected claim, depending on the payer.
6. If the patient or ID was wrong, fix the registration and resubmit under the right member.
7. If the death date on file is wrong, the record must be fixed at its source. Noridian says the beneficiary’s family or estate must contact the Social Security Administration. Then resubmit.
8. If the service was on the day of death, send an appeal with the chart and the times. Noridian says a redetermination may be submitted in that case.
9. Do not bill the patient or the estate for a CO adjustment.

Medicare, commercial and Medicaid notes

Medicare. The OIG report above describes the automatic rejection. Noridian’s CARC 13 page lists the next steps: verify the date of service, correct it and resubmit as a new claim, or request a redetermination when the death date and service date are the same day.

Commercial. Plans update death dates from their own sources. Ask the payer where the date came from and how to correct it.

Medicaid. State programs keep their own eligibility files and edit lists. Check the state provider manual and companion guide.

Worked example (illustrative)

A practice bills 99213 for a visit it believes happened on 12 March 2025. The charge was keyed as 12 March 2026. The remit shows CAS*CO*13*120.00, and the eligibility response shows a date of death in February 2026.

Reading it: The service date on the claim is later than the death date on file, so the edit fired and the whole charge was adjusted.

Check: The schedule and the chart note both show the visit on 12 March 2025, so the year was a keying error and the patient was alive on that date.

Fix: The biller corrects the date of service and resubmits the claim. The biller also adds a charge-entry check that flags any service date that falls after a known death date.

Second scenario: The chart shows the visit and the date of death are the same day, and the patient was seen before death. The biller appeals with the chart note, the visit time and the payer’s records request.

Prevention checklist

• [ ] Run eligibility on the day of service and again before billing.
• [ ] Stop recurring orders and rentals when you learn of a death.
• [ ] Add an edit for service dates after a known death date.
• [ ] Review charge entry for year and month typos before the claim goes out.
• [ ] Confirm patient identity with two identifiers at registration.
• [ ] Keep the CARC and RARC guide handy for staff training.

Related denial codes

• CO-31: patient cannot be identified as the payer’s insured.
• CO-27: expenses incurred after coverage terminated.
• CO-16: claim lacks information or has a billing error.
• CO-109: claim not covered by this payer or contractor.
• CARC and RARC guide.

Key takeaways

CO-13 means the death date on file is earlier than the service date on the claim. Check the service date, the patient match, and the death date, in that order. Fix the claim or the record, then resubmit. Appeal only when the facts support the service.

FAQ

Quick facts

Item	Value
X12 code	13
X12 start	01/01/1995
Official wording	The date of death precedes the date of service
Usual group	CO
CMS 2005 group for CARC 13	CO
Common confusions	CO-14 (birth date), CO-31 (member not found)
Last reviewed	16 October 2026

Sources

• X12, Claim Adjustment Reason Codes (CARC 13, 14, 16, 27, 31). CARC 13 Start 01/01/1995. Accessed 16 Oct 2026.
• CMS, Medicare Claims Processing Manual (IOM 100-04), Ch. 22, §60.1 Group Codes. Accessed 16 Oct 2026.
• CMS, Transmittal 470, Standardization of Fiscal Intermediary Use of Group and Claim Adjustment Reason Codes (4 Feb 2005). Accessed 16 Oct 2026.
• HHS OIG, Medicare Payments for Service Dates After Individuals’ Dates of Death, A-07-16-05089 (October 2016). Accessed 16 Oct 2026.
• Noridian Medicare, Reason Code 13 (JD DME), updated 25 Oct 2024. Accessed 16 Oct 2026.

Code wording and Medicare rules on this page were checked on 16 October 2026 against X12, CMS, HHS OIG and Noridian sources.

Last reviewed: 16 October 2026 · This page is educational and doesn’t replace payer-specific contracts or coding rules.