Summary & Overview
HCPCS G9124: CML Disease-Status Assessment, Accelerated Phase
HCPCS Level II code G9124 denotes an oncology disease-status assessment for chronic myelogenous leukemia (CML) limited to Philadelphia chromosome positive and/or BCR-ABL positive patients in the accelerated phase who are not in hematologic, cytogenetic, or molecular remission. The code is designated for use in a Medicare-approved demonstration project and signals a narrowly defined clinical population where disease-status evaluation is being tracked under programmatic oversight. Nationally, this code matters for oncology providers participating in demonstration projects and for payers managing coverage and reporting for precision oncology populations.
Key payers covered in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise overview of the code’s clinical intent and settings, a breakdown of payer coverage implications, and the context for how the code fits into oncology service lines. The publication presents benchmark considerations where available and notes that specific modifier and taxonomy details are listed separately. This resource is intended to clarify the code’s clinical scope, typical sites of service, and relevance for providers and administrators working with CML patients in accelerated phase within demonstration-program contexts.
Billing Code Overview
HCPCS Level II code G9124 describes an oncology disease-status service specific to chronic myelogenous leukemia (CML) that is Philadelphia chromosome positive and/or BCR-ABL positive, for patients in the accelerated phase not in hematologic, cytogenetic, or molecular remission. The description indicates use within a Medicare-approved demonstration project.
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Service type: Oncology disease-status assessment for CML in accelerated phase
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Typical site of service: Oncology clinic or hospital outpatient setting, including sites participating in Medicare demonstration projects
Clinical & Coding Specifications
Clinical Context
A 58-year-old patient with a known history of Philadelphia chromosome–positive chronic myelogenous leukemia (CML) presents to a tertiary oncology center participating in a Medicare-approved demonstration project for targeted disease-status reporting. The patient is in an accelerated phase but currently not in hematologic, cytogenetic, or molecular remission. The clinical workflow begins with an oncology clinic visit by a hematologist/oncologist for review of symptoms, physical exam, and therapy response assessment. Laboratory studies (complete blood count with differential, peripheral smear), bone marrow aspiration and biopsy with cytogenetic testing (including karyotype and fluorescence in situ hybridization for the Philadelphia chromosome), and quantitative BCR-ABL PCR testing are ordered. The visit includes documentation of disease status specific to G9124 requirements, explicit notation of Philadelphia chromosome and/or BCR-ABL positivity, and confirmation that the patient is in accelerated phase and not in remission. Treatment decisions (tyrosine kinase inhibitor dosing adjustment, enrollment in the demonstration project, consideration of clinical trials, or referral for allo-transplant evaluation) are documented. Billing staff append appropriate modifiers and submit the G9124 HCPCS Level II code to Medicare as part of the demonstration project reporting, with the service typically provided in an outpatient oncology clinic or hospital outpatient department and occasionally in an academic research clinic setting.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|