Skip to main content

N310 Remark Code: Assumed or Relinquished Care Date

N310 means the date a provider assumed or relinquished care was missing, incomplete, or invalid. It usually applies when surgical care is split between providers, and the payer needs to know when each provider's portion began or ended.

Quick facts

Code
N310 (RARC N310)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The provider must correct the transfer-of-care date. The patient is not billed for this adjustment.
Official description
Missing/incomplete/invalid assumed or relinquished care date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N310 means

A global surgical package covers the surgery plus related care before and after. Sometimes that care is split: one surgeon operates and another provider handles postoperative management. Modifiers such as 54 (surgical care only) and 55 (postoperative management only) signal the split, and payers then need to know when care passed from one provider to the other. N310 tells you that transfer date was missing or invalid.

It is normally paired with CARC 16.

Common causes

  • A claim with modifier 55 was submitted without the date postoperative care was assumed.
  • A surgeon billing with modifier 54 didn’t report when care was relinquished.
  • The date entered is before the surgery date or after the claim’s dates of service.
  • Box 15 carries the date with a qualifier for something else, such as initial treatment.
  • The two providers reported conflicting dates, so the payer can’t divide the global period.

How to fix it

  1. Confirm the surgery date and the documented date of transfer of care (often recorded in a transfer note or discharge instructions).
  2. Enter the date with the correct qualifier in box 15, or where the payer instructs, and in the matching 837P date field.
  3. Coordinate with the other provider so both claims show consistent dates.
  4. Make sure the modifier on the claim matches the portion of care you provided.
  5. Resubmit with frequency code 7 and the original claim number.

How to prevent it

When your practice agrees to split global care, record the transfer date in a structured field shared with billing. Set claim edits so modifier 54 or 55 cannot go out without the corresponding date. A short written agreement with the other practice on who reports which date avoids conflicting claims. Related modifier issues are covered in our NCCI and modifiers guide.

Codes that may appear with N310

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information; N310 names the assumed or relinquished care date.
  • CO-4 (The procedure code is inconsistent with the modifier used.): May appear if the split-care modifier doesn't fit the procedure billed.
  • N318 (Missing/incomplete/invalid discharge or end of care date.): The discharge or end-of-care date is missing or invalid.
  • N335 (Missing/incomplete/invalid referral date.): The referral date is missing or invalid.
  • N301 (Missing/incomplete/invalid procedure date(s).): The procedure date is missing or invalid.

N310 FAQ

When do I need an assumed or relinquished care date?

Typically when billing only part of a global surgical package, such as postoperative management only (modifier 55) or surgical care only (modifier 54). Payer rules vary.

Where is it reported on the CMS-1500?

Box 15 has qualifiers for the date care was assumed and the date it was relinquished. Some payers ask for the dates in box 19 instead, so follow their instructions.

Do both surgeons need to report dates?

Usually each provider reports the date relevant to their portion: the surgeon who hands off reports when they relinquished care, and the provider who takes over reports when they assumed it.