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N98 Remark Code: Successful Test Stimulation Required

N98 means permanent implantation was denied because the patient had not demonstrated a successful test stimulation first. The payer requires at least a 50 percent improvement during the trial, measured through voiding diaries, before it covers the permanent device.

Code: N98 (RARC N98)
Status: Active In use since August 24, 2001.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The coverage prerequisite was not met, so the amount is generally the provider's loss absent a valid advance notice.
PR (Patient Responsibility): Patient liability is possible only if a proper advance notice of non-coverage was signed before the implant.
Official description: Patient must have had a successful test stimulation in order to support subsequent implantation. Before a patient is eligible for permanent implantation, he/she must demonstrate a 50 percent or greater improvement through test stimulation. Improvement is measured through voiding diaries.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What N98 means

For implanted urinary stimulation devices, coverage for the permanent system depends on a trial. During the test stimulation phase, the patient keeps voiding diaries, and the results are compared with baseline. N98 is used when the payer did not see evidence that the trial produced a 50 percent or greater improvement.

It often explains CARC 50 or CARC B15. The payer’s position is that the qualifying step either did not occur, was not documented, or did not reach the required threshold.

Common causes

No test stimulation claim or record is on file before the permanent implant date.
The trial was performed, but the baseline and trial diaries were not included in records sent to the payer.
Notes describe improvement in general terms (“patient doing much better”) without quantified diary data.
The improvement documented was below 50 percent.
The trial was billed by a different provider, and the payer could not link it to the implant claim.

How to fix it

Locate the diaries from before and during the trial, and calculate the improvement in the measure the payer’s policy uses.
Confirm the trial dates and, if another provider performed the trial, get their records.
Appeal with a summary table showing baseline, trial results, and percentage change, plus the diary pages themselves.
If the threshold was not met, the permanent implant does not qualify. Review advance notice documentation to determine liability.

How to prevent it

Make the diary comparison a required step before the permanent implant is scheduled, and file the calculated result in a predictable place in the chart. For planned procedures that need prior authorization, submit the trial results with the request; see authorization and referral denials.

Codes that may appear with N98

CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Not considered medically necessary without a qualifying trial result.
CO-B15 (This service/procedure requires that a qualifying service/procedure be received and covered.): The service requires that a qualifying service (here, the test stimulation) be received and covered.
CO-272 (Coverage/program guidelines were not met.): The payer's coverage guidelines for the device were not met.

N99 (Patient must be able to demonstrate adequate ability to record voiding diary data such that clinical results of the implant procedure can be…): Requires the patient to be able to keep reliable voiding diaries, which the trial depends on.
N96 (Patient must be refractory to conventional therapy (documented behavioral, pharmacologic and/or surgical corrective therapy) and be an appropriate…): Requires failed conventional therapy and surgical candidacy.
N97 (Patients with stress incontinence, urinary obstruction, and specific neurologic diseases (e.g., diabetes with peripheral nerve involvement) which…): Excludes stress incontinence, obstruction, and certain neurologic causes.

N98 FAQ

What counts as a 50 percent improvement?

The payer compares voiding diary results from before the trial with results during it. The key symptom, such as leakage episodes or voids, should improve by half or more. Check the payer policy for which measures it uses.

Do the diaries need to be submitted?

They should be in the medical record and available on request. Many denials happen because the record states the trial was successful without the diary data behind it.

Is the trial itself affected by N98?

N98 is aimed at the permanent implantation. The test stimulation is billed and evaluated on its own.

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