Medical Oncology Billing Services
Oncology billing is driven by treatment cycles. A single regimen can mean many infusion visits, each with a drug, an administration service, and supporting medications. The drugs are often expensive, so a single wrong unit or missing authorization can hold up a large amount of payment.
Records must also tell a clear story. Payers want the cancer diagnosis, the stage, the treatment plan, and the reason for each drug. Westmont Revenue Partners connects oncology practices with vetted billing experts who understand oncology billing and the detail needed to support chemotherapy and infusion claims.
Who this is for
- Medical oncologists in private practice
- Combined hematology and oncology groups
- Practices with an in-house infusion suite
- Hospital-affiliated cancer centers
- Community oncology networks
- Nurse practitioners and physician assistants in oncology
What gets billed
- New and established patient visits
- Chemotherapy infusions and additional hours
- Therapeutic and supportive infusions
- Hormonal injections for cancer treatment
- Venous access device flushes
- Drugs supplied by the practice
- Treatment planning and coordination visits
- Survivorship and follow-up visits
- Visits tied to chemotherapy encounters
Commonly billed codes
| Code | Type | What it covers |
|---|---|---|
| 99215 | CPT | Established patient office visit at a high level |
| 96413 | CPT | Chemotherapy infusion, first hour |
| 96415 | CPT | Chemotherapy infusion, each additional hour |
| 96365 | CPT | Therapeutic infusion, first hour |
| 96366 | CPT | Therapeutic infusion, each additional hour |
| 96402 | CPT | Hormonal cancer drug given by injection |
| 96523 | CPT | Flushing a venous access device in the office |
| Z51.11 | ICD-10-CM | Encounter for chemotherapy or immunotherapy |
| C50.911 | ICD-10-CM | Cancer of the right female breast, unspecified site |
| C91.10 | ICD-10-CM | Chronic lymphocytic leukemia, not in remission |
Note
Codes are examples for orientation, not a complete list, and do not guarantee coverage or payment. Always check current code sets and payer policy.
Billing challenges in oncology
Drug codes and units. Each drug has its own code with a set unit size, and doses must be converted correctly. A biller checks every order against the claim, including waste when allowed.
Infusion sequencing. Only one primary infusion code is billed per visit, with others reported as sequential or concurrent. A biller reads the administration record to apply the right hierarchy.
Diagnosis order. When treatment is the main reason for the visit, the encounter code usually comes first, followed by the cancer diagnosis. A biller confirms this order on each chemotherapy claim.
Prior authorization. Regimens often need approval by drug, by cycle, or both. A biller tracks authorization limits so an expiring approval does not interrupt therapy.
Buy-and-bill risk. Practices carry the cost of drugs until payment arrives. A biller follows claims closely and reviews underpayments against contracts.
Biosimilars and supportive drugs. Payers may prefer certain products. A biller keeps payer preference lists current so claims match the covered product.
Documentation for medical necessity. Payers look for stage, line of therapy, and supporting tests. A biller works with clinical staff to make the chart match payer criteria.
How Westmont can help
- Matching you with vetted billing experts experienced in oncology
- End-to-end revenue cycle support, from authorization through payment posting
- Denial management for drug, infusion, and medical necessity issues
- Credentialing support for new oncologists and payer enrollment
- Reporting by drug, payer, and denial reason
Frequently asked questions
How is a chemotherapy infusion billed?
The first hour uses one infusion code, and each extra hour uses an add-on. The drug is billed separately with its own code and units. Start and stop times in the record support the hours billed. Other infusions at the same visit follow sequencing rules. A biller reviews the record to apply them.
What order should diagnosis codes go in on chemo claims?
When the visit is mainly for chemotherapy or immunotherapy, coding guidelines generally place the treatment encounter code first, then the cancer diagnosis. Payers may also want other supporting codes. Check current guidelines and payer policy. A biller applies this consistently across claims.
Why are oncology drug claims denied?
Typical reasons include missing authorization, wrong units, off-policy diagnoses, and incomplete documentation of stage or prior treatment. Payers may also prefer certain products. A biller verifies each requirement before submission and manages appeals when needed.
What is buy-and-bill, and what are the risks?
Buy-and-bill means the practice buys the drug and bills the payer after giving it. The practice carries the cost until payment arrives, and underpayments can hurt cash flow. Tracking claims and checking payments against contract terms helps limit the risk.
Should an oncology practice outsource billing?
Many practices consider it when drug volume or authorizations become hard to manage. Westmont does not submit claims itself. We connect you with vetted billing experts, and you decide whether a match fits your practice.
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