RARC M86: Duplicate or Similar Service Already Paid
The payer flagged this service as a duplicate because the same or a very similar procedure was already paid within a recent time window — verify whether the service is truly distinct before resubmitting.
What Does RARC M86 Mean?
M86 appears when the payer's adjudication system detects that a claim line matches or closely resembles a service that has already been processed and paid. Payers use automated duplicate-detection logic that compares procedure codes, dates of service, and sometimes modifiers across recent claims for the same patient and provider. When a match is found, the system assumes the second submission is a duplicate and denies it rather than risk paying for the same service twice.
The challenge with M86 is that the payer's duplicate logic is not always perfectly calibrated. Legitimately distinct services can trigger duplicate flags when they share the same CPT code and fall on the same date or within a short window. For example, bilateral procedures, staged surgeries, or repeat diagnostic tests ordered for clinical reasons may all look like duplicates to an automated system. Similarly, if a claim was resubmitted to correct a different field (such as a modifier or diagnosis code), the system may see the original paid claim and the corrected resubmission as duplicates.
M86 is commonly paired with CARC 18 (exact duplicate claim) or CARC 97 (payment already made for the same service). The distinction matters: CARC 18 usually means the claim is byte-for-byte identical to a prior submission, while CARC 97 suggests the payer considers the service itself to be a duplicate even if the claim details differ slightly.
What to Do
Start by pulling the remittance for the previously paid claim that the payer considers the original. Compare dates of service, procedure codes, modifiers, and units. If the current claim truly is a duplicate submission, no further action is needed — the service was already paid. If the services are distinct (for example, a bilateral procedure or a clinically justified repeat), resubmit with documentation that differentiates the two claims. Adding appropriate modifiers (such as modifier 59 for distinct procedural services, or LT/RT for laterality) and including clinical notes that explain why the service was performed again can help override the duplicate flag.
If the denial stems from a corrected claim rather than a new service, consider submitting it as a formal corrected claim (claim frequency code 7) rather than a new submission, which tells the payer to replace the original rather than stack a new payment. This approach avoids the duplicate-detection trap entirely.
Common Scenarios
- A physician performs bilateral knee injections on the same day using the same CPT code, and the second claim line is denied as a duplicate because no laterality modifier was appended.
- A billing office resubmits a claim to correct a diagnosis code, but because the original claim was already paid, the payer's system flags the resubmission as a duplicate rather than a correction.
- A patient has two separate E/M visits on the same day — one in the morning for an acute issue and one in the afternoon for a scheduled follow-up — and the second visit is denied with M86 because both share the same date of service and evaluation code.
Commonly Paired With
RARC M86 commonly appears alongside these CARC denial codes: