Summary & Overview
HCPCS G9513: Medication Adherence — PDC Less Than 0.8
HCPCS Level II code G9513 denotes that a patient’s proportion of days covered (PDC) for prescribed medications was less than 0.8, flagging suboptimal adherence. Nationally, adherence measures such as PDC are central to chronic disease management, quality reporting, and value-based payment arrangements because they correlate with outcomes and utilization. Use of G9513 standardizes documentation of nonadherence across care teams and payers.
Key payers considered in this context include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise explanation of what G9513 represents, typical clinical settings where it is applied, and how it fits into adherence monitoring workflows. The publication also covers common benchmarking approaches, how payers incorporate adherence indicators in quality programs, and the clinical relevance of a PDC threshold below 0.8.
This summary is intended for a national audience of clinicians, billing and coding staff, care managers, and policy analysts. It focuses on the code’s clinical meaning, operational implications for documentation and reporting, and the policy context around medication adherence measures. Data not available in the input will be identified where applicable.
Billing Code Overview
HCPCS Level II code G9513 indicates that an individual did not have a proportion of days covered (PDC) of 0.8 or greater. This code documents suboptimal medication adherence as measured by the PDC metric.
Service type: Adherence assessment / Medication management monitoring
Typical site of service: Outpatient clinical settings, pharmacy-managed programs, care coordination services, or any setting where medication adherence monitoring is performed
Data not available in the input.
Clinical & Coding Specifications
Clinical Context
A patient with multiple chronic conditions is undergoing medication reconciliation and adherence assessment during a care management encounter. The health plan or clinician calculates the proportion of days covered (PDC) for a key medication class (for example, statins or diabetes agents) over a measurement period and determines the individual did not reach a PDC of 0.8 or greater. Typical workflow: patient presents for a routine follow-up or telehealth visit; pharmacy fill data are reviewed by the clinician or care manager; medication fill dates and days supply are entered into the EMR or quality measurement system; PDC is calculated and found to be below 0.8; the result is documented and the G9513 HCPCS Level II code is appended to the claim to indicate nonadherence for quality reporting. Typical site of service: outpatient clinic, primary care office, care management or case management telehealth encounter, or specialty clinic managing chronic medications.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when services required substantially greater work than typical for the visit documenting PDC assessment and associated counseling. |