Official X12 description
“This service/procedure requires that a qualifying service/procedure be received and covered. The qualifying other service/procedure has not been received/adjudicated.”
Source: X12 Claim Adjustment Reason Codes. The X12 External Code Lists are the single authoritative source for every CARC descriptor — always verify against the current release before building a claim-scrub rule.
What CARC B15 actually means
CARC B15 is a sequencing denial — the payer requires a 'qualifying' service to be on file (and paid) before the billed service can be adjudicated. The classic example is Medicare's requirement that a skilled-nursing-facility stay be preceded by a qualifying 3-day inpatient hospital stay, or that certain advanced procedures require a preceding diagnostic study. The fix is to locate and bill the qualifying service first, or document why it is not needed.
Common root causes
- Qualifying service (prior hospital stay, diagnostic study, conservative therapy) has not been billed or has not adjudicated yet.
- Qualifying service was rendered by an out-of-network provider and never billed to this payer.
- Sequence of care did not require a qualifying service but the payer's edit treats it as required.
Prevention checklist
- Care-pathway awareness at scheduling — for procedures with qualifying-service prerequisites, confirm the prerequisite is documented before scheduling.
- For SNF admissions, verify the qualifying 3-day inpatient hospital stay before billing.
- When the qualifying service was at an external facility, obtain the records early so the payer's records-on-file check passes.
Appeal strategy — step by step
Most CARC B15 denials clear faster with the right remediation than with a formal appeal. Work the steps in order and escalate only when a lower-effort path has been ruled out.
- 1Identify the qualifying service, confirm it was billed and paid, and resubmit the current claim after the qualifying claim adjudicates.
- 2If the qualifying service was external, submit the external records with an appeal letter referencing the payer's specific prerequisite policy.
- 3If the sequence of care medically did not require the qualifying service, appeal with clinical justification and a citation to the guideline permitting the deviation.
Sample appeal-letter language for CARC B15
Edit the bracketed fields before sending. This template is a starting point; a payer-specific appeal form may still be required — check the provider portal first.
Payer-specific notes
Payer-specific behavior for CARC B15 publishes here as the QuickIntell anonymized denial ETL ingests sufficient volume. In the meantime, consult the payer directory for the relevant provider manual and appeal form.
How common is CARC B15?
Out of 306 seeded CARCs, ranked by combined US monthly search volume for "CARC B15", "CO-B15 denial", and "denial code B15".
Platform frequency ranks publish once the anonymized denial-rate pipeline reaches the publication threshold (strategy §12 Phase 2).
How QuickRCM prevents CARC B15
QuickRCM catches the root causes above before the 837 leaves the clearinghouse:
- Claim-scrub rules fire on every root cause listed above — the scrub references the same X12 CAS segment logic that drives the denial, so what the payer checks, QuickRCM checks first.
- When a denial lands, QuickRCM routes it to the correct worker with the documentation bundle already attached (op note, LCD citation, modifier rationale, EOB, primary 835).
- Appeal templates tuned to each CARC (including this one) pull the supporting facts from the claim and fill the bracketed fields automatically.
CAQH CORE code combinations for CARC B15
Under the CAQH CORE Payment and Remittance Uniform Use rule, health plans may pair CARC B15 only with the remark codes and group codes below for the defined business scenario 3 (Billed service not covered by the health plan). A combination outside this list on an 835 is itself a payer compliance issue worth raising.
| RARC | Remark description | Group code | Scenario |
|---|---|---|---|
| (no RARC) | CARC used without a remark code | CO, PI or PR | 3 |
| M25 | The information furnished does not substantiate the need for this level of service. If you believe the service should have been fully covered as billed, or if you did not know and could not reasonably have been expected to know that we would not pay for this level of service, or if you notified the patient in writing in advance that we would not pay for this level of service and he/she agreed in writing to pay, ask us to review your claim within 120 days of the date of this notice. If you do not request an appeal, we will, upon application from the patient, reimburse him/her for the amount you have collected from him/her in excess of any deductible and coinsurance amounts. We will recover the reimbursement from you as an overpayment. | CO, PI or PR | 3 |
| M51 | Missing/incomplete/invalid procedure code(s). | CO, PI or PR | 3 |
| M80 | Not covered when performed during the same session/date as a previously processed service for the patient. | CO, PI or PR | 3 |
| M114 | This service was processed in accordance with rules and guidelines under the DMEPOS Competitive Bidding Program or a Demonstration Project. For more information regarding these projects, contact your local contractor. | CO, PI or PR | 3 |
| MA133 | Claim overlaps inpatient stay. Rebill only those services rendered outside the inpatient stay. | CO, PI or PR | 3 |
| N20 | Service not payable with other service rendered on the same date. | CO, PI or PR | 3 |
| N67 | Professional provider services not paid separately. Included in facility payment under a demonstration project. Apply to that facility for payment, or resubmit your claim if: the facility notifies you the patient was excluded from this demonstration; or if you furnished these services in another location on the date of the patient's admission or discharge from a demonstration hospital. If services were furnished in a facility not involved in the demonstration on the same date the patient was discharged from or admitted to a demonstration facility, you must report the provider ID number for the non-demonstration facility on the new claim. | CO, PI or PR | 3 |
| N115 | This decision was based on a Local Coverage Determination (LCD). An LCD provides a guide to assist in determining whether a particular item or service is covered. A copy of this policy is available at www.cms.gov/mcd, or if you do not have web access, you may contact the contractor to request a copy of the LCD. | CO, PI or PR | 3 |
| N122 | Add-on code cannot be billed by itself. | CO, PI or PR | 3 |
| N130 | Consult plan benefit documents/guidelines for information about restrictions for this service. | CO, PI or PR | 3 |
| N386 | This decision was based on a National Coverage Determination (NCD). An NCD provides a coverage determination as to whether a particular item or service is covered. A copy of this policy is available at www.cms.gov/mcd/search.asp. If you do not have web access, you may contact the contractor to request a copy of the NCD. | CO, PI or PR | 3 |
| N674 | Not covered unless a pre-requisite procedure/service has been provided. | CO, PI or PR | 3 |
| N682 | Missing/Incomplete/Invalid history of prior periodontal therapy/maintenance. | CO, PI or PR | 3 |
| N748 | Adjusted because the related hospital charges have not been received. | CO, PI or PR | 3 |
| N784 | Missing comprehensive procedure code. | CO, PI or PR | 3 |
Frequently asked questions — CARC B15
What does CARC B15 mean?
CARC B15 is an X12 Claim Adjustment Reason Code. The official definition is: "This service/procedure requires that a qualifying service/procedure be received and covered. The qualifying other service/procedure has not been received/adjudicated." In plain English, the payer is telling you cARC B15 is a sequencing denial — the payer requires a 'qualifying' service to be on file (and paid) before the billed service can be adjudicated. The classic example is Medicare's requirement that a skilled-nursing-facility stay be preceded by a qualifying 3-day inpatient hospital stay, or that certain advanced procedures require a preceding diagnostic study. The fix is to locate and bill the qualifying service first, or document why it is not needed.
How do I resolve a CARC B15 (CO-B15) denial?
Start with the most common root cause: Qualifying service (prior hospital stay, diagnostic study, conservative therapy) has not been billed or has not adjudicated yet. First step: Identify the qualifying service, confirm it was billed and paid, and resubmit the current claim after the qualifying claim adjudicates. See the full remediation and appeal checklist on this page before filing a formal appeal.
Is CARC B15 patient responsibility?
No — CARC B15 is typically carried under CO (Contractual Obligation) or OA (Other Adjustment), which means it is the provider's responsibility, not the patient's. Do not bill the patient unless the 835 CAS group code is PR.
What does CARC B15 look like on an EOB or 835 remittance?
On the 835 ERA, CARC B15 appears in Loop 2110 CAS segment as "CAS*CO*B15*{amount}". On a paper EOB the same code prints in the Adjustment/Denial Reason column with the X12 description: "This service/procedure requires that a qualifying service/procedure be received and covered. The qualifying other servi…" — usually paired with one or more RARC remark codes in the same remittance line for additional context.
Which RARC is paired with CARC B15?
CARC B15 is commonly observed with RARC M62, N130. The RARC narrows the reason — for example, pointing at a missing modifier, an LCD citation, or a specific policy. Fix the underlying CARC first; the RARC usually clears with the corrected claim.
Disclaimer
This page is operational reference for medical-billing professionals. It is not legal, clinical, or contractual advice. X12 code descriptors are maintained by the X12 External Code Lists; always verify against the current X12 release and the payer's own published policy before submitting or appealing a claim.