Buy-and-Bill vs Pharmacy Benefit Manager Coverage

Buy-and-bill dominates wherever a clinician administers a drug directly to a patient. Oncology is the largest spending category by a significant margin: chemotherapy regimens, monoclonal antibodies, supportive biologics delivered in an infusion chair. Rheumatology follows, with biologics for rheumatoid arthritis and psoriatic arthritis given in physician offices or infusion suites. Neurology, particularly MS infusions, and dermatology's injectable biologics round out the heaviest buy-and-bill specialties. The shared characteristic is clinical workflow. The provider purchases the drug, holds it in inventory, administers it, and bills the insurer.

The pharmacy benefit channel covers oral and self-administered specialty drugs by default, because there is no clinical workflow through which a provider would take ownership of a drug the patient manages themselves. But the boundary does not stop there, and this is the part that consistently catches practices flat-footed. Payers increasingly route provider-administered drugs through the pharmacy benefit via white or brown bagging, even when the drug requires clinical administration in an office or infusion center. A plan can cover the same drug under both benefits at the same time. The ownership chain changes; the clinical act does not.

The data reflects where the balance of power currently sits. As of the most recent IQVIA reporting, 98.5% of medical oncology products still flow through buy-and-bill. But payer pressure on that number is structural, not episodic. Specialty drugs represent fewer than 2% of the patient population and account for more than 55% of total U.S. drug spending, with average annual costs exceeding $100,000 as of 2025. At that financial scale, payers have every incentive to contest which channel controls distribution, because the channel is what determines who captures the margin. Think of it as a tollbooth on a highway: whoever owns the booth collects the fee, regardless of who built the road.

How Providers Are Reimbursed Under Buy-and-Bill, and Where the Margin Comes From

Under Medicare Part B, the formula is ASP plus 6%. The provider's margin is the spread between what they actually paid to acquire the drug and what ASP+6% reimburses. When acquisition cost is negotiated below ASP, that spread widens. When a practice pays close to or above ASP, it compresses, and the economics stop working.

Commercial insurance is different. Markups under commercial contracts typically run ASP+20% to ASP+30%, sometimes higher. That is substantially more margin than Medicare, which explains why commercial buy-and-bill accounts are operationally valuable to practices in ways that Medicare volume alone simply is not.

Here is where the structural incentive problem lives: because the markup is a percentage of price, the absolute dollar margin is larger for expensive brand biologics than for lower-cost biosimilars, even when the two agents are clinically equivalent. A provider administering a brand biologic at $15,000 per dose captures more return than one administering a biosimilar at $9,000, even at the same reimbursement percentage. Policy has tried to address this. The Inflation Reduction Act introduced a biosimilar reimbursement adjustment effective 2025, reimbursing biosimilars at ASP+8% for their first five years post-launch. It is a deliberate prescribing incentive, and whether it moves behavior meaningfully is still playing out.

The IRA's longer-term Part B impact is more significant. CMS reported an average discount of 63% off list price in the first round of negotiated drug prices. For Part B drugs subject to negotiation, maximum fair price plus 6% replaces ASP+6% beginning in 2028. When MFP-based reimbursement becomes the ceiling, the absolute dollar margin on those drugs compresses materially, and that compression will alter prescribing patterns and push more volume toward white bagging or specialty pharmacy distribution.

Site of care compounds everything. Oliver Wyman research commissioned by AHIP in 2024 found that among the top ten specialty drugs by total claim dollars, buy-and-bill costs were between 50% and 103% higher through a hospital outpatient department compared to a physician office. Same drug, same J-code, different site of service. Payers are paying close attention to that number.

What White Bagging Is and How Payers Use It to Redirect Drugs Into the Pharmacy Benefit

White bagging is a payer-mandated policy in which a specialty pharmacy, typically one affiliated with the payer's parent organization, ships the drug directly to the provider's office or infusion center before the appointment. The provider administers the drug but did not purchase it, does not own it, and cannot bill for it. The specialty pharmacy adjudicates the drug cost through the pharmacy benefit. The provider bills only for the professional administration service.

That revenue shift is the whole point. Oliver Wyman and AHIP research found that provider markups on specialty drugs added more than $13 billion to commercial health insurance premiums in 2024. White bagging is payers' direct cost-containment response to that figure. Routing the drug through an affiliated specialty pharmacy captures the spread that would otherwise flow to the provider.

UnitedHealthcare's white-bagging requirements applied to more than 100 specialty and oncology supportive drugs, plus certain gene therapies, for commercial plan members. That is not a narrow carve-out. It is a structural redistribution of revenue at scale. MMIT Oncology Index data cited by Drug Channels Institute shows that at physician offices, white bagging has been the dominant sourcing method for roughly 15% to 20% of covered commercial lives over the past five years. Buy-and-bill remains dominant overall, but this trend is not cyclical. It is payer strategy, and it has a direction.

Brown bagging is the more disruptive variant. The specialty pharmacy ships the drug to the patient, who then transports it to the provider for administration. Every step of that chain introduces handling variability, temperature excursion risk, and chain-of-custody gaps that white bagging at least partially avoids by shipping directly to the clinical site. Neither arrangement was designed with clinical workflow in mind. That much is obvious to anyone who has worked in an infusion center. The system was built for billing convenience, not bedside care.

Why Providers and Clinicians Push Back Against White-Bagging Mandates

The AMA and ASCO have jointly characterized mandatory white and brown bagging as a direct threat to patient access and to physicians' ability to deliver timely, consistent care. The clinical objections are concrete.

When a drug arrives pre-shipped from an external specialty pharmacy, the provider loses control over preparation and handling. For hazardous oncology agents, sterility and compounding integrity are not abstractions; they are the reasons we have infusion nurses and oncology pharmacists in the room. More immediately: if a patient's weight has changed, if labs come back outside the expected range, or if their clinical status requires a dose adjustment on the day of administration, the pre-shipped dose is the wrong dose. The practice cannot administer it. The dose is wasted, and the practice must handle disposal of a toxic agent it never ordered and cannot return. That is not a hypothetical edge case. That happens regularly.

Operationally, external specialty pharmacies are not integrated into clinical workflow. Auto-shipments continue regardless of what is happening with the patient. A drug arrives for someone who discontinued therapy two weeks ago. Now the practice has an unusable toxic agent, a frustrated patient, and an administrative problem with no clean resolution.

The financial displacement is not minor, either. Under buy-and-bill, drug margin is a revenue line that funds staff, infrastructure, and overhead. Under white bagging, that line disappears and transfers to the affiliated specialty pharmacy. For independent oncology practices and smaller infusion centers, the loss of drug revenue can threaten operational viability outright. This is not hypothetical. It has closed practices.

Several states have responded with anti-white-bagging or right-to-choose legislation. As of 2025, this remains an active and genuinely unresolved policy battleground, with legislative outcomes varying significantly by state.

How Patient Cost-Sharing Differs Depending on Which Benefit Covers the Drug

The benefit channel does not just determine who bills for the drug. It determines what the patient owes, and the difference can be significant enough to stop treatment.

Under the medical benefit, many commercial plans apply low or no cost-sharing for drugs administered in a hospital outpatient setting, often bundling drug cost into the facility or professional claim. The patient's out-of-pocket exposure is minimal. Under the pharmacy benefit, specialty drugs occupy the highest formulary tier, almost always subject to coinsurance rather than a flat copay. Typical specialty tier coinsurance runs 25% to 33% of drug cost. For a drug priced at $8,000 per month, 25% coinsurance is $2,000 the patient owes per fill. The Kaiser Family Foundation's 2025 Employer Health Benefits review found that 84% of covered workers are enrolled in plans with three or more drug tiers, and 60% in plans with four or more. Specialty drugs sit at the top of that structure.

Shifting drugs from buy-and-bill to white bagging lowers total payer costs while simultaneously raising patient out-of-pocket obligations. The payer's savings do not flow through to the patient when the pharmacy benefit's cost-sharing structure is more burdensome than the medical benefit's. The patient absorbs the difference. In that sense, white bagging is like a company cutting costs by switching to a cheaper supplier — the savings rarely show up on the customer's receipt.

Medicare adds its own layer. Under Part B, buy-and-bill carries 20% coinsurance with no hard cap, though supplemental coverage often absorbs most of that. Under Part D, the IRA's $2,000 annual out-of-pocket cap effective in 2025 represents meaningful financial protection for Medicare beneficiaries whose high-cost specialty drugs move through the pharmacy benefit. USC Schaeffer Center analysis covering 2020 through 2024 found that stand-alone Part D plans shifted toward coinsurance structures for preferred brands over that period, increasing beneficiary cost exposure, while Medicare Advantage plans generally offered lower and more predictable cost-sharing with more zero-deductible structures.

For revenue cycle teams, the benefit channel determines the patient's financial liability before a single claim is submitted. Benefit investigation is a patient financial risk assessment, not just a coverage confirmation.

How PBM Market Concentration Shapes Coverage Decisions Across Both Channels

Three PBMs, CVS Caremark, Express Scripts, and Optum Rx, processed approximately 80% of all equivalent prescription claims in 2024, per Drug Channels Institute estimates. The FTC's July 2024 Interim Report found that the top six PBMs processed more than 90% of the roughly 6.6 billion prescriptions dispensed by U.S. pharmacies in 2023, and that pharmacies affiliated with the three largest PBMs account for nearly 70% of all specialty drug revenue. Those numbers are not background noise. They are the structural context in which every coverage decision gets made.

Five of the six largest PBMs are now owned by entities that also own a health insurer. The same parent company can set the formulary, operate the specialty pharmacy receiving the white-bagged drug, and administer the health plan issuing the white-bagging mandate. The financial incentive to route drugs through the affiliated pharmacy rather than through the independent provider's buy-and-bill workflow is not incidental to the structure. It is the operating logic of it. Ask yourself: why did the PBM cross the road? Because it owned the road, the toll booth, and the pharmacy on the other side.

Drug Channels Institute estimates that the total value of manufacturers' gross-to-net reductions for all brand-name drugs reached $334 billion in 2023. Those rebate flows concentrate through the same three PBMs. Rebate negotiation influences which drugs sit on formulary, at what tier, and subject to which utilization management requirements, including channel mandates. The coverage determination that lands on a provider's desk is the output of a system with its own financial logic, and that logic was not organized around clinical considerations or patient cost-sharing outcomes. I say that not to alarm anyone, but because understanding the incentive structure is the only way to navigate it intelligently.

What Coverage Verification and Benefit Investigation Need to Establish Before Treatment

The foundational question benefit investigation must answer is this: is the drug covered under the medical benefit, the pharmacy benefit, or both, and does the plan mandate a specific channel? Everything else flows from that answer.

The same drug can carry different coverage terms, different prior authorization requirements, and different patient cost-sharing depending on which benefit applies. A plan can technically cover a drug under both benefits while mandating white bagging for the pharmacy side, which changes the claim type, removes the practice as the billing entity for the drug, and alters the patient's financial liability in ways the patient almost certainly did not anticipate.

For buy-and-bill claims under the medical benefit, coding accuracy is not optional. The correct J-code for the specific drug must be paired with the appropriate administration HCPCS code. Biosimilar coding introduces additional complexity because the correct J-code or Q-code varies by payer, and errors generate denials regardless of whether coverage actually exists. Site of service must also be confirmed. Reimbursement rates differ between a physician office and a hospital outpatient department for the same drug and the same J-code. Billing under the wrong site creates either underpayment or a compliance exposure, and neither outcome resolves cleanly.

Prior authorization is required for most specialty drugs in both channels, but the process, the approving entity, and the clinical criteria can differ materially between the medical and pharmacy benefit. Benefit investigation must confirm which channel's PA pathway governs, because initiating the wrong PA process delays treatment and does not satisfy coverage requirements. I have seen this mistake made by experienced teams. It is easy to make and slow to fix.

Patient financial liability must be assessed as part of benefit investigation, not as an afterthought. If the applicable benefit's cost-sharing structure creates an obligation the patient cannot meet, that needs to be identified before the appointment, not after the drug has been administered and billed. Manufacturer patient assistance programs and financial counseling have lead times. Benefit investigation is what creates the space to use them.

When a payer mandates white bagging, the practice's revenue cycle workflow changes substantially. The practice bills only for administration. Coordination with the specialty pharmacy's shipping and PA timelines must be synchronized with the clinical schedule, and the practice needs a protocol for drugs that arrive for patients who have discontinued therapy, had a dose change, or are no longer candidates for that agent. That protocol does not exist automatically. Someone has to build it before the first shipment arrives, not after.

The regulatory landscape is not static. The IRA's negotiated pricing terms for Part B drugs take effect in 2028. The $2,000 Part D out-of-pocket cap became effective in 2025. Coverage policies, formulary placements, and cost-sharing terms for the same drugs will shift as those provisions phase in. Benefit verification completed at the start of a treatment course is not permanent. Returning patients require re-verification. The channel assignment and cost-sharing structure that applied in one benefit year will not necessarily apply in the next, and assuming otherwise is precisely how practices get caught.