CO-186: Level of Care Change Adjustment
The payer downgraded the level of care and the difference is the provider's write-off. Appeal with strong clinical documentation to recover the full amount.
What Does CO-186 Mean?
CO-186 is the most common pairing and means the difference between the billed level of care and the payer-approved level is the provider's contractual write-off. The provider cannot bill the patient for this difference. This is a payment reduction, not a full denial — the payer is paying at the lower level, and the provider must absorb the gap unless an appeal overturns the downgrade.
CARC 186 shows up on your remittance when the payer makes a level of care adjustment — most commonly downgrading the billed service to a lower-acuity level. This is not an outright denial of the service; the payer agrees the patient received care, but disagrees with the intensity or setting that was billed. The result is a reduced payment based on the lower level of care the payer deems appropriate.
This code hits hardest in inpatient and facility settings. A common scenario is billing for inpatient admission when the payer determines that observation status would have been sufficient. It also frequently occurs with E/M levels — billing a level 5 office visit when the payer's review concludes a level 3 or 4 was warranted based on the documentation. Payers typically use clinical criteria tools like InterQual or Milliman to make these determinations, and if the medical record does not meet their thresholds, they will downgrade.
The financial impact can be significant because the gap between the billed level and the approved level often represents a substantial dollar amount. Under CO, the provider must write off this difference. Under PR, the patient's cost-sharing may change based on the adjusted service level. Appeals are common and often successful when the provider can demonstrate that the original level of care was medically necessary with strong clinical documentation.
Common Causes
| Cause | Frequency |
|---|---|
| Inadequate documentation to support billed level of care The medical records do not adequately support the level of care that was billed, such as missing progress notes, incomplete patient condition records, or insufficient clinical justification | Most Common |
| Payer determines lower level of care was appropriate The payer's utilization review or medical necessity determination concludes that a lower level of care than what was billed would have been sufficient for the patient's condition | Most Common |
| Incorrect level of care coding The procedure or revenue codes used on the claim indicate a higher level of care than what was actually provided or documented in the medical record | Common |
| Failure to meet payer-specific criteria for billed level The payer has specific clinical criteria (such as InterQual or Milliman) for each level of care, and the claim does not meet those criteria | Common |
| Missing pre-authorization for higher level of care The higher level of care required pre-authorization from the payer, and it was not obtained before the service was rendered | Common |
How to Resolve
Review the clinical documentation against the payer's level of care criteria, and appeal with medical necessity evidence if the original level was justified.
- Compare billed vs. approved level Identify the exact dollar difference between the billed level and the approved level. This quantifies what is at stake in the appeal.
- Gather clinical evidence Compile all medical records, lab results, imaging reports, and physician notes that support the medical necessity of the originally billed level of care.
- Submit a clinical appeal File an appeal with a detailed clinical narrative explaining why the higher level of care was medically necessary. Reference the payer's specific clinical criteria and demonstrate how the patient met them.
- Request peer-to-peer if needed If the written appeal is denied, request a peer-to-peer review where the treating physician can discuss the case directly with the payer's medical director.
Common RARC Pairings
The RARC code tells you exactly what triggered the CO-186:
| RARC | Description |
|---|---|
| N386 | This decision was based on a National Coverage Determination or Local Coverage Determination |
| N657 | The level of care has been changed based on clinical review |
How to Prevent CO-186
- Document the clinical indicators that justify the billed level of care thoroughly at the time of service
- Obtain pre-authorization for higher levels of care when required by the payer
- Train clinical staff on the specific clinical criteria (InterQual, Milliman) that payers use for level of care determinations
- Conduct concurrent utilization reviews during the patient's stay to ensure ongoing documentation supports the billed level
General Prevention
- Ensure thorough and accurate documentation of the patient's condition, clinical indicators, and medical necessity for the level of care at the time of service
- Obtain pre-authorization for higher levels of care before the service is rendered, following payer-specific requirements
- Train clinical and coding staff on payer-specific level of care criteria such as InterQual or Milliman guidelines
- Conduct concurrent utilization reviews to verify the patient continues to meet criteria for the billed level of care throughout their stay
- Perform regular audits of level of care coding to identify and address patterns of downgrades
Also Filed As
The same CARC 186 may appear with different Group Codes:
Related Denial Codes
Sources
- https://www.mdclarity.com/denial-code/186
- https://droidal.com/blog/medical-billing-denial-codes/
- Codes maintained by X12. Visit x12.org for official definitions.