Buy-and-bill is the reimbursement model where a practice purchases a provider-administered drug, administers it to the patient, and then bills the payer for the drug (its J-code or Q-code) and the administration (a CPT infusion or injection code) as two separate line items on the same claim. The practice fronts the acquisition cost; the payer reimburses after the claim adjudicates — typically at ASP + 6% for drugs on the CMS Average Sales Price file, trimmed by the mandatory 2% sequestration cut. It is the default model for oncology, rheumatology, neurology, and other infusion-heavy specialties, and it predates the newer specialty-pharmacy channels (white bagging, brown bagging) built around drugs that route through the pharmacy benefit instead.
Most physician-administered biologics and infused drugs can't be dispensed the way an oral prescription is — they require a clinical setting, controlled storage and handling, and a clinician to draw and administer the dose. CMS built Medicare Part B's drug-payment rules around a provider holding, administering, and billing the drug directly, which is what buy-and-bill formalizes — the broader logic behind that split is covered on the medical vs. pharmacy benefit reference page. The reimbursement formula — Average Sales Price plus 6% — comes from the Medicare Modernization Act of 2003 and is codified in the Medicare Claims Processing Manual, Pub 100-04, Chapter 17. CMS recalculates ASP every calendar quarter from manufacturer-reported sales data, and the per-unit payment limit moves with it.
This site binds its buy-and-bill claim math to the CMS Q2 2026 Average Sales Price file — 887 Part B drug billing codes — across 417 specialty and infusion drugs in the CareCost drug library, each with a live-updating data-asp price.
The gap between stage 1 (the practice pays cash) and stage 4 (the practice gets paid) is the entire financial risk of buy-and-bill. A denied prior authorization, a downcoded administration CPT, or a payer that reimburses below acquisition cost all land on the practice after the drug has already been bought and given — there's no way to "return" an administered dose. That lag, typically two to six weeks depending on the payer, is why inventory discipline and clean prior-authorization documentation matter more in buy-and-bill than in almost any other billing workflow in the practice.
Buy-and-bill is one of three ways a provider-administered drug can reach the patient. The other two — white bagging and brown bagging — route the drug through the pharmacy benefit instead of the medical benefit, which changes who owns the inventory risk and how the claim is built.
A full comparison of white bagging's billing mechanics, payer mandates, and denial patterns lives on the white-bagging reference page. The short version for a biller triaging which model applies to a given claim: if the practice's own inventory and NDC were used, it's buy-and-bill; if a specialty pharmacy shipped a patient-labeled unit, it's white bagging, and the drug does not get billed again on the medical claim.
Keytruda (pembrolizumab) is billed under J9271, supplied in 100 mg single-dose vials. The standard adult dose is a flat 200 mg — exactly two vials, with no discarded drug, so the claim carries JZ rather than JW.
Drugs with body-surface-area or weight-based dosing rarely land on an exact vial multiple the way Keytruda's flat dose does. See Abraxane and Avastin for buy-and-bill examples where a JW waste line changes the economics, and the billing units calculator to run the vial math for any drug and dose without doing it by hand.
Buy-and-bill touches more roles in the practice than a typical office-visit claim, because the financial exposure starts before the claim is ever built.
| Role | Responsibility |
|---|---|
| Prior-auth / benefits coordinator | Verifies medical-necessity documentation and secures PA approval before the drug is ordered — the single biggest lever for avoiding a denied, already-administered dose. Confirms whether the payer requires site-of-care restrictions or mandates a specialty-pharmacy channel instead of buy-and-bill for that drug. |
| Inventory / pharmacy manager (or clinical lead in smaller practices) | Orders the drug from a wholesaler, distributor, or 340B contract pharmacy; manages par levels and cold-chain storage; tracks NDC and lot numbers per administration for J-code and waste documentation. |
| Clinical staff (nurse/infusion tech) | Draws and administers the dose, documents the vial(s) opened, dose administered, and any discarded amount in the medical record — the source data for the JW/JZ decision. |
| Biller / coder | Builds the claim: J-code with correct units, administration CPT matched to route/complexity/time, JW/JZ and 340B modifiers as applicable. Reconciles the paid amount against acquisition cost to catch negative-spread claims. |
| Practice manager / RCM lead | Owns the cash-flow view across the acquisition-to-reimbursement lag, tracks denial and underpayment patterns by payer and drug, and decides when a drug's economics no longer justify buy-and-bill versus routing a payer to white bagging. |
Buy-and-bill is the model where a practice purchases a provider-administered drug (typically an infused or injected biologic), stores it, administers it to the patient, and then bills the payer for both the drug (via its HCPCS J-code or Q-code) and the administration (via a CPT infusion/injection code). The practice fronts the acquisition cost and is reimbursed after the claim adjudicates, which is the opposite order from a pharmacy-benefit fill where the pharmacy is typically paid closer to the point of dispensing.
For drugs on the CMS Average Sales Price (ASP) file, the Medicare Part B payment limit is ASP + 6% per billing unit — set quarterly by CMS. The mandatory 2% Medicare sequestration cut applies to the Medicare-paid 80% of that amount (patient coinsurance is unaffected), which nets to roughly ASP + 4.3% on the blended claim once both the Medicare payment and the patient's 20% coinsurance are counted. The administration CPT code (96413, 96365, 96372, etc.) is reimbursed separately under the Medicare Physician Fee Schedule (MPFS), not the ASP system.
In buy-and-bill, the practice purchases and owns the drug, then bills the medical benefit using its own NDC and lot. In white bagging, a specialty pharmacy purchases and owns the drug, then ships a patient-specific, pre-labeled unit to the practice for administration — the practice bills only the administration CPT, not the drug's J-code, because the drug was billed on the pharmacy benefit. White bagging shifts inventory risk off the practice but adds coordination overhead (matching the exact patient/date/dose to a shipped vial) and can create waste-billing problems if the shipped quantity does not match what the vial-and-dose math calls for. See the white-bagging reference page for the full comparison.
The practice does. It pays the distributor or manufacturer for the drug up front — often weeks before the claim is submitted, adjudicated, and paid — and carries that inventory cost on its books. If a prior authorization is denied after the drug has already been administered, or if a payer pays less than the acquisition cost (a negative spread), the practice absorbs the loss. This upfront capital and denial risk is the single biggest operational argument practices raise against buy-and-bill relative to white bagging, where the specialty pharmacy carries the inventory risk instead.
A buy-and-bill claim carries at least two line items: the drug itself, billed under its HCPCS J-code or Q-code (e.g., J9271 for pembrolizumab) at the number of billing units administered, and the administration, billed under a CPT infusion or injection code from the 96360–96417 family (or 96401–96402 for chemo injections) chosen by route, complexity, and time. Single-dose-container claims also require the JW (discarded) or JZ (zero discarded) modifier on the drug line, and 340B-acquired drugs append TB, the sole 340B identifier since CMS discontinued JG on January 1, 2025.
Usually, yes, for high-cost specialty drugs. Because the practice is financially exposed until the claim pays, most buy-and-bill workflows treat prior authorization as a hard gate before the drug is ordered, not just before it is billed — ordering ahead of PA approval is how practices end up holding drug inventory they cannot get reimbursed for. Confirm PA status and medical-necessity documentation before the vial is opened, not after.
data-asp bindings read from.All sources are publicly available federal publications or paraphrased from trade-association educational materials. The methodology by which we resolve source disagreements is described in the Methodology.