Summary & Overview
HCPCS A9559: Cobalt Co-57 Cyanocobalamin Oral Diagnostic Dose
HCPCS Level II code A9559 denotes a diagnostic radiopharmaceutical: cobalt co-57 cyanocobalamin, oral, per study dose up to 1 microcurie. This code is used to bill for the radiolabeled vitamin B12 compound when administered for diagnostic testing, typically in outpatient imaging centers or hospital outpatient departments. The code is relevant nationally for facilities that perform specialty nuclear medicine or metabolic absorption studies and for payers that cover diagnostic radiopharmaceuticals.
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 clinical use and billing context for A9559, including service line placement, typical sites of service, and common billing considerations. The publication also outlines benchmark topics readers can expect: how this HCPCS Level II code is categorized within radiopharmaceutical billing, common modifiers that may be applied (listed elsewhere), and implications for documentation and coding workflows. National stakeholders—hospital billing teams, imaging centers, and payers—will gain clarity on where this code fits in diagnostic service portfolios and what to expect when encountering oral cobalt co-57 cyanocobalamin studies in claims.
Billing Code Overview
HCPCS Level II code A9559 represents cobalt co-57 cyanocobalamin, oral, diagnostic, per study dose, up to 1 microcurie. This code describes a diagnostic radiopharmaceutical preparation used in oral diagnostic studies where cobalt-labeled cyanocobalamin is administered in trace amounts.
Service Type: Diagnostic radiopharmaceutical administration
Typical Site of Service: Outpatient imaging centers or hospital outpatient departments
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Clinical & Coding Specifications
Clinical Context
A typical patient is an adult referred for evaluation of vitamin B12 absorption or suspected pernicious anemia using an oral radiolabeled cobalt-57 cyanocobalamin absorption study. The patient presents to an outpatient nuclear medicine or diagnostic radiology clinic after fasting as instructed. A technologist documents patient identity, recent B12 supplementation, and medications that alter absorption (eg, proton pump inhibitors, metformin). The patient ingests the oral diagnostic dose A9559 (cobalt Co-57 cyanocobalamin, oral, up to 1 microcurie). Serial blood samples or whole-body/abdominal gamma camera imaging are obtained per protocol at specified time points to measure tracer absorption and retention. Nuclear medicine physicians interpret quantitative results to differentiate malabsorption, gastric intrinsic factor deficiency, or noncompliance. Results are communicated to the referring clinician for diagnosis and management planning. Typical sites of service are outpatient nuclear medicine departments, diagnostic radiology clinics, or hospital outpatient imaging centers.
Coding Specifications
| Modifier | Description | When to Use |
|---|---|---|
00 | No modifier | Use when no modifier applies to the service |
| 22 | Increased procedural services | Use when the procedure requires significantly greater effort or time than usual (rare for standard oral tracer studies)