Buy‑and‑Bill Denial Prevention: Top 10 Root Causes and How to Fix Them

Under the traditional buy-and-bill model, practices purchase the medication, administer it, and seek reimbursement. However, this process is rife with potential denial triggers. Based on common infusion center experiences, here are the top 10 root causes of buy-and-bill claim denials and solutions for each:

1. Incomplete or Incorrect Patient Information: Simple errors like wrong member ID, date of birth, or missing insurance updates can cause outright denials. Fix: Verify and re-verify patient demographics and insurance details at referral and again prior to billing. Use a checklist to ensure all required fields (patient ID, group #, etc.) are correct.

2. Inadequate Prior Authorization: Most infusions require pre-authorization. A denial may occur if auth was not obtained or documentation was lacking. Fix: Check payer policies before treatment. Obtain written prior auth and confirm it covers the specific drug, dose, and number of visits. If urgent treatment starts before auth, contact the payer for a retro-auth as soon as possible.

3. Incorrect Coding or Missing Modifiers: Coding mistakes – such as wrong J-code, mis-keyed units, or omitted modifiers – frequently lead to denials. Fix: Double-check coding guidelines for the drug and administration. Ensure the HCPCS code matches the drug’s NDC (see crosswalk guide) and that units reflect the dose given. Use required modifiers (e.g., –JW for waste, –59 for separate infusions) correctly. Even small unit errors can trigger Medicare’s MUE edits and denial.

4. Coverage Limitations / Policy Exclusions: The payer’s medical policy might not cover the drug for the given diagnosis or may require failure of alternatives. Fix: Review the payer’s coverage policy or formulary for that medication. If policy requires step therapy or has an exclusion, be prepared to submit a medical necessity letter or evidence of prior therapies tried (see section on necessity letters). Sometimes using an insurer-preferred biosimilar instead of a reference biologic can avoid a denial.

5. Failure to Meet Medical Necessity Requirements: A claim can be denied if the payer deems the infusion not medically necessary for that patient (often due to insufficient documentation). Fix: Document thoroughly the diagnosis, prior treatments and failures, and the clinical rationale for this therapy. For oncology, include staging and guideline references; for immunologic conditions, include relevant lab results. Submit supporting records with the claim or on appeal to demonstrate necessity.

6. Timely Filing Missed: Each payer has a deadline (e.g., 90 days) to submit claims. Missing that window = denial. Fix: Establish internal turnaround targets for claims (e.g., within 7 days of infusion). Use billing software alerts for nearing filing limits. If a claim is held up (e.g., waiting on coding info), communicate with the payer to obtain an extension or submit an incomplete claim to get it on record, then follow up.

7. Duplicate or Overlapping Billing: Submitting the same claim twice or billing a drug separately while also on a global service can result in denials. Fix: Ensure each infusion is billed once. If multiple units are needed, put on one claim line with appropriate units rather than duplicate lines (unless instructed for JW). Also coordinate benefits if the patient has primary and secondary insurance to avoid the appearance of duplicate billing across payers.

8. Lack of Required Documentation: If the claim isn’t backed by physician orders, infusion notes, or required forms, payers may deny or delay it. Fix: Maintain a documentation checklist: physician’s order on file, treatment note with drug name/dose, start-stop times, patient tolerance, etc. For specialty drugs, include required REMS or distribution enrollment proof if applicable. Having this ready can expedite response to any additional info requests.

9. NDC or Drug Detail Missing: Many payers require the drug’s NDC number, quantity, and unit of measure on the claim (especially for “J-code” drugs). If omitted or invalid, claims deny. Fix: Always include the 11-digit NDC for each drug, the NDC unit of measure (e.g., “ML” or “UN”), and quantity on the claim form in the designated fields. Ensure the NDC is active and corresponds to the billed J-code (mismatches cause rejection). About 10% of infusion claim rejections trace back to NDC errors, so capturing this correctly is crucial.

10. Site-of-Service or “Buy-and-Bill” Restrictions: In recent trends, some payers mandate certain expensive infusions be obtained via specialty pharmacy (white bagging) instead of buy-and-bill. If a provider bills buy-and-bill contrary to policy, it denies. Fix: Verify during benefits check if the payer requires an alternate sourcing. If so, either coordinate white bagging or seek a site-of-care exception with medical necessity reasoning (e.g., patient needs hospital supervision). Proactively addressing this prevents surprise denials for using the “wrong” supply channel.