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N344 Remark Code: TENS Trial End Date Missing or Invalid

N344 means the end date of the patient's Transcutaneous Electrical Nerve Stimulator (TENS) trial was missing, incomplete, or invalid, so the payer could not measure the trial or confirm it finished before the purchase.

Quick facts

Code
N344 (RARC N344)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): A correctable data problem with the trial end date. The supplier supplies the correct date; the patient is not billed for this adjustment.
Official description
Missing/incomplete/invalid Transcutaneous Electrical Nerve Stimulator (TENS) trial end date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N344 means

Where a payer requires a TENS trial, it measures the trial between two dates. N344 addresses the second one: the day the trial concluded. If that date is missing, partial, or out of sequence (for example, earlier than the start date or later than the purchase), the payer can’t tell whether the trial met its minimum length and whether the purchase came afterward.

Like its companion code for the start date, N344 usually explains CARC 16 on the purchase claim. A trial that turns out to be too short can lead to CARC 108.

Why the end date fails

Suppliers often track rental start dates carefully and let the end date default to “open.” Other common problems:

  • The last billed rental month was used as the end date, even though the device was returned or converted earlier.
  • The practitioner’s evaluation date was entered, but the device was used for days after that.
  • The trial was extended, and the original planned end date stayed on the claim.
  • The end date overlaps the purchased unit’s date of service.

Steps to resolve

  1. Reconcile the rental record: when did the trial device stop being billed or used?
  2. Match that to the practitioner’s note documenting results and the decision to purchase.
  3. Enter the confirmed end date in the location the payer’s TENS billing guidance specifies, and make sure the start date is present too.
  4. Confirm the sequence is start date, then end date, then purchase date of service.
  5. Submit a corrected claim with frequency code 7. If the actual dates do not meet the payer’s trial rule, do not adjust them; review whether the purchase is billable.

How to prevent it

Close out every trial rental in your system with an explicit end date when the practitioner makes the purchase decision. A pre-billing check that compares trial dates with the payer’s minimum length avoids sending purchase claims that cannot be paid.

Codes that may appear with N344

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Information is missing; N344 identifies the TENS trial end date.
  • CO-108 (Rent/purchase guidelines were not met.): Rent or purchase guidelines were not met, which may apply if the trial was too short or overlaps the purchase.
  • N343 (Missing/incomplete/invalid Transcutaneous Electrical Nerve Stimulator (TENS) trial start date.): Covers the start of the TENS trial rather than its end.
  • N342 (Missing/incomplete/invalid test performed date.): Used for a missing or invalid date of a qualifying test.
  • N336 (Missing/incomplete/invalid replacement date.): Addresses a missing or invalid replacement date for equipment.

N344 FAQ

When does a TENS trial end?

It ends when the practitioner evaluates the results and the trial rental stops, typically just before a purchase begins. Use the date shown in your rental records and the practitioner's note.

Can the trial end date be the same as the purchase date?

Payer rules differ on overlap. Many expect the trial to end before the purchased unit's date of service, so check the payer's policy for the exact sequence.

What if the trial was cut short?

Report the actual end date. A trial shorter than the payer's minimum may not support a purchase, and changing the date to meet the minimum would be inaccurate.