Summary & Overview
HCPCS G9512: Medication Adherence, PDC 0.8 or Greater
HCPCS Level II code G9512 denotes that an individual achieved a proportion of days covered (PDC) of 0.8 or greater, a common benchmark for medication adherence. Nationally, this code is used in quality measurement, performance reporting, and care coordination to document adherence to chronic therapies and to support value-based programs. Its use can influence quality scores, payer performance metrics, and population health management workflows.
Key payers in national analyses include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of the code’s clinical meaning and typical operational contexts, a summary of payer coverage patterns, and guidance on where the code is applied within quality reporting and care-management processes. The publication covers benchmarking considerations for PDC-based measures, relevant billing and documentation practices tied to adherence reporting, and policy updates that affect use of adherence codes in payer programs.
The report is intended for health plan managers, clinician leaders, revenue cycle professionals, and quality improvement teams seeking a concise reference on G9512 for national program alignment and reporting purposes.
Billing Code Overview
HCPCS Level II code G9512 indicates that an individual had a proportion of days covered (PDC) of 0.8 or greater. This code documents medication adherence as measured by PDC at or above the common 80% threshold.
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Service type: Medication adherence measurement and reporting
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Typical site of service: Ambulatory care or administrative/quality measurement settings where pharmacy fill data or claims-derived adherence metrics are evaluated
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult with chronic cardiovascular disease or diabetes enrolled in a medication adherence monitoring program. During a routine medication reconciliation visit (in-person or telehealth), the clinician or pharmacist calculates the Proportion of Days Covered (PDC) for the patient’s maintenance medication regimen. When the calculated PDC is 0.8 or greater, the billing code G9512 is used to document that the patient met the adherence threshold. The workflow commonly includes: medication list verification, pharmacy fill history review (often via claims or state prescription monitoring), PDC calculation for a defined measurement period (typically 90–365 days), documentation of counseling or care coordination as indicated, and submission of the G9512 code on the claim to indicate adherence met. Typical sites of service are outpatient clinics, ambulatory pharmacy consultation areas, chronic care management visits, or telehealth encounters where medication adherence assessment and documentation occur.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
22 | Increased procedural services | Use when additional documentation supports substantially greater effort for the encounter when calculating or documenting PDC beyond typical complexity. |
23 | Unusual anesthesia | Use only if anesthesia was required and unusual during an associated service documented on the same claim (rarely applicable to adherence coding).
52 | Reduced services | Use when the adherence assessment or associated service was partially reduced or not fully performed.
53 | Discontinued procedure | Use when the adherence assessment process was started but discontinued due to patient or clinical factors.
54 | Surgical care only | Not typically applicable; include only if coding combined services on same claim where this applies.
55 | Postoperative management only | Not typically applicable; include only if applicable with related surgical services.
56 | Preoperative management only | Not typically applicable; include only if applicable with related surgical services.
62 | Two surgeons | Use when two practitioners of equal specialty level participated in an associated procedure on the same claim.
AS | Physician assistant, nurse practitioner, or clinical nurse specialist services for Medicare beneficiaries | Use when the service was performed by an eligible non-physician practitioner under Medicare rules.
CO | Cast or other immobilization | Rarely applicable; include only if an unrelated service on the same claim requires this modifier.
CQ | Service furnished by a CRNA under direction of a contract anesthesiologist | Rarely applicable; include only if anesthesia services are billed with the adherence service.
FX | Physician or practitioner never an owner of the facility | Use when billing rules require identifying practitioner ownership status on the claim.
FY | Eligible nonparticipating physician or supplier | Use when the clinician is nonparticipating with Medicare and this status must be reported.
QK | Medical direction of two or more CRNAs by a physician | Rarely applicable; include only if anesthesia is billed with the adherence service.
| Taxonomy Code | Specialty | Notes |
|---|---|---|
207Q00000X | Internal Medicine | Primary clinicians managing chronic disease and medication therapy. |
207R00000X | Family Medicine | Outpatient providers who perform medication adherence assessments.
193200000X | Pharmacist | Pharmacists performing medication therapy management and PDC calculations.
363L00000X | Nurse Practitioner | Advanced practice providers performing adherence counseling and documentation.
261QP0400X | Clinical Nurse Specialist | Specialists involved in chronic disease management and adherence programs.
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
E11.9 | Type 2 diabetes mellitus without complications | Chronic condition where medication adherence (PDC ≥ 0.8) is critical to control and quality measurement. |
I10 | Essential (primary) hypertension | Long-term antihypertensive therapy adherence is commonly tracked using PDC.
I25.10 | Atherosclerotic heart disease of native coronary artery without angina pectoris | Secondary prevention medications require high adherence; PDC is used for quality metrics.
E78.5 | Hyperlipidemia, unspecified | Statin adherence is commonly measured with PDC for cardiovascular risk management.
J45.909 | Unspecified asthma, uncomplicated | Controller inhaler adherence may be monitored using PDC for chronic respiratory disease management.
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
99490 | Chronic care management, at least 20 minutes of clinical staff time directed by a physician or other qualified health care professional, per calendar month | Often billed for ongoing care management where PDC assessment supports eligibility and documentation. |
99487 | Complex chronic care management services, with care plan, per calendar month | Used when the patient has multiple chronic conditions and the PDC assessment is part of complex care planning.
99605 | Medication therapy management service(s) provided by a pharmacist, initial 15 minutes, face-to-face with patient, initial assessment and intervention plan (Note: CPT varies by payor; pharmacists commonly use alternative billing routes) | Pharmacist-performed medication reviews and PDC calculations frequently accompany MTM services.
99457 | Remote physiologic monitoring treatment management services, 20 minutes or more of clinical staff/physician/other qualified health care professional time in a calendar month | When adherence monitoring is performed via telehealth or remote monitoring platforms and documented time meets requirements.
99078 | Physician education services for groups of patients | Used when adherence education is delivered to patient groups and PDC outcomes are discussed as program metrics.