Summary & Overview
CPT 0559U: MammoCheck BF9 Antigen ELISA for Breast Cancer Monitoring
CPT code 0559U denotes a Proprietary Laboratory Analyses (PLA) test for MammoCheck™, a blood‑based ELISA that measures the BF9 antigen to monitor breast cancer response to therapy or disease progression. As a PLA code, 0559U applies only to the single, manufacturer‑specific test produced by Milagen Inc., and it is used for reporting when that unique assay is performed. Nationally, PLA codes like 0559U are important because they enable distinct billing and tracking for proprietary diagnostics that may have unique clinical roles or coverage considerations.
Key payers discussed include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find a concise synopsis of the clinical purpose of the test and where it is typically performed, plus an overview of payer coverage considerations and coding context. The publication covers benchmarks and payer policy themes relevant to proprietary laboratory assays, summarizes common modifiers reported with this code, and provides clinical context for how BF9 measurements are intended to inform therapeutic monitoring. Data not available in the input will be explicitly noted where applicable.
Billing Code Overview
CPT code 0559U is a Proprietary Laboratory Analyses (PLA) code that is specific to a single commercial test: MammoCheck™ from Milagen Inc. The test is a blood‑based enzyme‑linked immunosorbent assay (ELISA) that measures the BF9 antigen protein level in a patient’s serum. Results are used to assess whether breast cancer is responding to therapy or showing signs of progression or regression.
Service Type: Proprietary laboratory analysis / serum protein assay (ELISA)
Typical Site of Service: Clinical laboratory or outpatient phlebotomy collection site with laboratory processing
Clinical & Coding Specifications
Clinical Context
A typical patient scenario involves a woman with a history of diagnosed breast carcinoma who is undergoing systemic therapy and requires monitoring for treatment response. A medical oncologist orders the proprietary blood-based test MammoCheck™ (0559U) to measure serum levels of the BF9 antigen via ELISA. A phlebotomy draw is performed in an outpatient oncology clinic, hospital outpatient lab, or independent clinical laboratory. The specimen is processed and sent to Milagen Inc. (the performing laboratory/manufacturer) for analysis. Results are returned to the ordering oncologist and used as an adjunctive objective marker to help evaluate tumor response, detect biochemical progression, or support decisions about imaging follow-up or therapy modification. Typical encounters include surveillance visits during chemotherapy, targeted therapy, or endocrine therapy, and during evaluation of suspected progression when imaging findings are equivocal.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | Default, no modifier appended; service without special circumstances | Use when reporting the test under routine circumstances without special reporting needs |
22 | Increased procedural services | Use when additional work or evaluation beyond typical testing is documented (rare for PLA but applicable if substantial extra work is required) |
52 | Reduced services | Use when the test specimen or components are limited and the laboratory performs a reduced version of the protocol |
53 | Discontinued procedure | Use if specimen collection or processing was started but discontinued before completion for clinical reasons |
59 | Distinct procedural service | Use if another unrelated lab procedure is reported the same day and documentation supports distinct testing (append only if payer accepts for PLA) |
90 | Reference (outside) laboratory | Use when the performing lab refers testing to another laboratory (note: PLA codes typically identify a single lab; use only if indicated) |
96 | Hemo/Transfusion service, multiple procedures | Use when reporting related complex laboratory testing within a single encounter if payer accepts modifier application |
TC | Technical component | Use when billing entity provides only technical component and professional component is billed separately (rare for PLA codes but applicable if split billing occurs) |
26 | Professional component | Use when billing only the professional interpretation component is provided by the ordering physician or pathologist |
| Taxonomy Code | Specialty | Notes |
|---|---|---|
| 207Q00000X | Medical Oncology | Ordering and clinical interpretation of tumor response markers |
| 2086S0300X | Hematology & Oncology | Specialists who manage systemic cancer therapy and monitoring |
| 207L00000X | Clinical Laboratory | Laboratories performing or coordinating specimen collection and testing |
| 207K00000X | Clinical Pathology | Pathologists overseeing laboratory testing and quality control |
| 2083P0200X | Oncology Nurse Practitioner | Advanced practice providers who order tests and manage therapy monitoring |
Related Diagnoses
| ICD-10 Code | Description | Clinical Relevance |
|---|---|---|
C50.911 | Malignant neoplasm of unspecified site of right female breast | Primary breast cancer diagnosis for which BF9 monitoring may be ordered to assess response to therapy |
C50.912 | Malignant neoplasm of unspecified site of left female breast | Primary breast cancer diagnosis for which BF9 monitoring may be ordered to assess response to therapy |
C50.919 | Malignant neoplasm of unspecified site of breast, unspecified | Used when laterality is unspecified; BF9 testing may be ordered for disease surveillance |
C79.81 | Secondary malignant neoplasm of breast | Used when metastatic deposits to the breast exist; BF9 may help monitor systemic disease activity |
Z85.3 | Personal history of malignant neoplasm of breast | Used in surveillance contexts where prior breast cancer is present and BF9 monitoring is part of follow-up care |
Related CPT Codes
| CPT Code | Description | Relationship to This Procedure |
|---|---|---|
36415 | Collection of venous blood by venipuncture | Commonly performed immediately before 0559U to obtain the serum specimen for BF9 ELISA testing |
81000 | Urinalysis, by dipstick or tablet reagent for bilirubin, glucose, hemoglobin, ketones, etc. | Often performed as part of routine clinic labs at the same visit though not directly related to BF9 measurement |
80053 | Comprehensive metabolic panel (CMP) | Frequently ordered alongside tumor marker testing to assess organ function during systemic therapy |
86336 | Antibody; direct measurement, each (e.g., quantitative) | Represents immunoassay methodology analogous to the ELISA technique used for BF9 measurement; not a substitute for the PLA code |
88342 | Immunohistochemistry, per specimen; initial single antibody stain | May be used in parallel when tissue-based biomarkers are assessed in addition to blood-based BF9 testing |