PR-108: Rent/Purchase Guidelines Not Met

What Does PR-108 Mean?

PR-108 means the patient bears financial responsibility because rental or purchase guidelines were not met, typically due to patient-side factors. The most common scenario is CPAP compliance failure — Medicare and many commercial payers require patients to demonstrate a minimum number of hours of nightly use (typically 4 hours per night for 70% of nights) during the initial rental period. If the patient fails to meet compliance thresholds, the rental is terminated and the patient becomes liable.

CARC 108 fires when a payer determines that the billing for a rented or purchased item — almost always durable medical equipment (DME) — did not comply with the payer's specific rental/purchase guidelines. Every major payer, and Medicare in particular, maintains detailed rules governing how DME items transition from rental to purchase, what documentation is required at each stage, and what modifiers indicate the current billing phase.

Medicare's capped rental program is the most common context for this denial. Under capped rental, certain DME items (wheelchairs, hospital beds, CPAP machines) must be rented for up to 13 months before ownership transfers to the patient. Each month requires a specific modifier, and the billing must reflect the correct point in the rental cycle. Submitting a purchase claim during the rental window, using the wrong month's modifier, or missing the certificate of medical necessity (CMN) will all trigger CARC 108.

The financial outcome depends on the Group Code. CO-108 is the standard assignment, meaning the provider must absorb the denied amount as a contractual write-off until the guideline violation is corrected. PR-108 occurs less frequently and typically involves patient non-compliance with equipment use requirements — such as failing to meet CPAP compliance thresholds — where the patient's plan transfers the denied amount to the patient.

Common Causes

How to Resolve

Identify which specific rental/purchase guideline was violated, correct the documentation or coding, and resubmit or appeal with proof of compliance.

1. Verify the PR assignment Confirm the denial is genuinely patient responsibility and not a provider billing error that should be coded as CO. Review whether the guideline violation is patient-related (compliance failure) or provider-related (coding error).
2. Check patient compliance records If the denial is related to equipment compliance (e.g., CPAP usage), review the patient's compliance data to determine if they actually met the threshold or if data was not submitted to the payer.
3. Assist the patient if correctable If the patient can still meet compliance requirements or if compliance data was not submitted, work with the patient and ordering physician to document compliance and resubmit before billing the patient.
4. Bill the patient if valid If the PR assignment is correct and the patient failed to meet guideline requirements, bill them with an explanation of which requirement was not met and what steps they can take going forward.

How to Prevent PR-108

• Educate patients on equipment compliance requirements immediately at the time of delivery — explain CPAP usage thresholds, follow-up visit schedules, and documentation renewal deadlines
• Set up automated reminders for patients approaching compliance checkpoints and documentation renewal dates
• Verify patient-specific plan requirements for DME coverage before delivering equipment, and ensure patients understand their obligations

General Prevention

• Educate patients on compliance requirements for rented equipment, particularly CPAP usage requirements and follow-up visit schedules
• Set up automated patient reminders for equipment compliance milestones and documentation renewal deadlines
• Verify patient-specific plan requirements for DME coverage before initiating equipment delivery

Also Filed As

The same CARC 108 may appear with different Group Codes:

Related Denial Codes