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M59 Remark Code: 'To' Date of Service Invalid

M59 means the 'to' date of service, the end of the billed service period, is missing, incomplete, or invalid. The payer could not determine how long the service ran and did not process the line.

Quick facts

Code
M59 (RARC M59)
Status
Active In use since January 1, 1997; last modified February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The line is unpaid until a valid end date is supplied. The patient is not billed for date errors.
Official description
Missing/incomplete/invalid 'to' date(s) of service.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What M59 means

M59 is the end-date counterpart of M52. Where services are billed across a range, such as a rental month or a series of visits, the claim line carries both a start and an end date. The payer found the end date missing, malformed, before the start date, or otherwise impossible.

It usually comes with CARC 16 and may result in the claim being returned unprocessed.

Common causes

  • Span-billed services were submitted with only a ‘from’ date.
  • The ‘to’ date is in the future, often because a rental was billed in advance.
  • The ‘to’ date falls outside the institutional statement covers period.
  • The number of days billed does not match the date span.
  • Keying errors in month or year.

How to fix it

  1. Confirm the actual end date of the service from the record or rental log.
  2. Correct the ‘To’ column in box 24A, or the institutional line and statement dates.
  3. Recheck units so they agree with the date span.
  4. Resubmit as a new claim if returned, or with resubmission code 7 if processed.

How to prevent it

Do not release span-billed claims until the end of the billing period, and add an edit that compares units against the date range. See the CO-16 guide for other data errors.

Codes that may appear with M59

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Required information, the end date, is missing or invalid.
  • M52 (Missing/incomplete/invalid 'from' date(s) of service.): The starting ('from') date is the problem instead.
  • MA31 (Missing/incomplete/invalid beginning and ending dates of the period billed.): The overall billing period dates are missing or invalid.
  • M53 (Missing/incomplete/invalid days or units of service.): Days or units may conflict with the dates billed.

M59 FAQ

When does a 'to' date matter most?

For services billed over a span of dates, such as monthly DME rentals, a range of dialysis or therapy days, or institutional statement periods.

Can the 'to' date be the same as the 'from' date?

Yes. For single-day services, the dates are usually the same. Some payers accept a blank 'to' date for single-day professional services.

Why is a date in the future a problem?

A claim generally cannot bill for service dates that have not yet occurred. The end date must be on or before the claim submission date.