Summary & Overview
CPT 96366: Additional Hour for Therapeutic/Diagnostic IV Infusion
Headline: CPT 96366: Add-on Hourly IV Infusion for Therapeutic, Prophylactic, or Diagnostic Care
Lead: CPT 96366 is the add-on code used to report each additional hour of a non-chemotherapy intravenous infusion provided for therapeutic, prophylactic, or diagnostic purposes. It supplements the primary initial infusion code and is relevant across outpatient and office-based infusion services.
What this code represents and why it matters: CPT 96366 captures incremental infusion time beyond the first hour, enabling accurate reporting of extended infusion services. Nationally, precise use of this add-on code affects billing clarity, encounter documentation, and claims adjudication for prolonged IV infusions that are not chemotherapy.
Key payers covered: The analysis addresses major commercial and public payers including Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare.
Overview of what readers will learn: This publication explains the clinical and billing context for CPT 96366, distinguishes it from the initial infusion code and other additional-hour codes, and outlines typical sites of service. Readers will find benchmarks for code usage, common documentation elements associated with extended infusion time, and a summary of payer considerations and policy language affecting claim acceptance. The content highlights coding relationships and operational implications for infusion centers and office-based providers. Data not available in the input where applicable will be noted.
CPT Code Overview
CPT 96366 describes an intravenous infusion provided for therapy, prophylaxis, or diagnosis, billed as each additional hour and used as an add-on in conjunction with the primary infusion procedure.
Service type: Therapeutic/prophylactic/diagnostic non-chemotherapy IV infusion – add-on
Typical site of service: Office (POS 11) or Hospital Outpatient (POS 19)
Clinical & Coding Specifications
Clinical Context
A 62-year-old outpatient with metastatic lung cancer presents to the oncology clinic for supportive electrolyte repletion and therapeutic drug administration. The patient is scheduled for a multihour intravenous infusion of a non-chemotherapy agent (for example, intravenous iron, electrolyte replacement, or biologic therapy) following clinic triage and nursing assessment. The Infusion Therapy Registered Nurse starts the IV, programs the infusion pump, monitors vital signs and infusion tolerance, documents the start and stop times, and notifies the supervising Hematology & Oncology Physician for any adverse events. The initial hour of infusion is reported with the primary infusion code (e.g., 96365), and each subsequent completed additional hour is reported with the add-on code 96366. Typical sites of service include Office (POS 11) and Hospital Outpatient (POS 19).
Coding Specifications
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Modifiers
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59— Distinct Procedural Service: Use when the additional hourly infusion represented by96366is a distinct service from other procedures performed on the same day and documentation supports a separate procedural service. -
76— Repeat Procedure or Service by Same Physician or Other Qualified Health Care Professional: Use when96366is billed for a repeated infusion hour because the same service was performed more than once by the same provider during the same day and documentation supports repetition. -
Associated Provider Taxonomies
| Taxonomy Code | Specialty |
|---|---|
163WI0600X | Infusion Therapy Registered Nurse |
207RI0011X | Interventional Cardiology Physician |
207RH0003X | Hematology & Oncology Physician |
Related Diagnoses
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Z51.11— Encounter for antineoplastic chemotherapyRelevant when IV therapeutic or supportive infusions are administered in the context of chemotherapy care coordination or as an adjunct to antineoplastic therapy.
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Z51.81— Encounter for therapeutic drug level monitoringRelevant when IV infusion therapy is associated with monitoring therapeutic drug levels that guide dosing and infusion duration.
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C34.90— Malignant neoplasm of unspecified part of unspecified bronchus or lungRelevant as an underlying oncologic diagnosis for which supportive or therapeutic IV infusions (non-chemotherapy) may be provided.
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D63.0— Anemia in neoplastic diseaseRelevant when IV therapy (for example, iron or transfusion-related supportive infusions) is provided for anemia associated with malignancy.
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E87.6— HypokalemiaRelevant when IV electrolyte replacement is administered for clinically significant hypokalemia during an outpatient infusion visit.
Related CPT Codes
| CPT Code | Description | Relationship to 96366 |
|---|---|---|
96365 | Intravenous infusion, for therapy, prophylaxis, or diagnosis (specify substance or drug); initial, up to 1 hour | Primary/initial infusion code. 96366 is reported in addition for each additional completed hour after the initial hour billed with 96365. These codes are commonly billed together when an infusion exceeds one hour. |
96367 | Therapeutic, prophylactic, or diagnostic IV infusion; additional sequential infusion, up to 1 hour | Alternative/additional add-on code for sequential additional infusions of up to 1 hour. 96367 may be used for sequential separate infusions; 96366 is for each additional hour following the primary procedure. |
National Reimbursement Benchmarks
National commercial averages (BUCA) have a mean allowed rate of $31.47 for 96366, which is higher than Medicare’s mean of $22.20 by $9.27. Blue Cross Blue Shield and UnitedHealth Group show mean commercial rates near or above the BUCA average, while Medicare remains substantially lower than the commercial mix.
Dispersion measured as the difference between the 75th and 25th percentiles is tightest for Medicare (range $2.00) and Aetna (range $14.00), though Medicare’s tightness reflects a narrow national fee schedule. The widest dispersion appears for UnitedHealth Group (range $19.50) and Cigna (range $18.00), indicating greater variability in allowed rates across providers for those payers. The table and chart below present the full percentile and mean-rate breakdown.
Trek Health ingests and normalizes Transparency in Coverage data and payer policy updates to give provider organizations a clear view of how commercial reimbursement behaves across markets, payers, and services. Our platform transforms raw payer disclosures into structured intelligence that supports contract evaluation, payer negotiations, and service line strategy. By combining market benchmarks with ongoing policy visibility, Trek helps teams identify variability, risk, and opportunity in commercial reimbursement. The result is faster insight, stronger negotiating positions, and more informed financial decisions.