← The Infusion Reimbursement Index

The Infusion Reimbursement Index — Methodology

Issue 01, v2.0 · Vintage 2026-Q2-06 · Published 2026-08-12

These are **contracted rates published in insurers' own machine-readable files — not amounts

paid on a claim.** Every figure in the report is a contracted rate unless explicitly labelled

otherwise. Nothing here describes what a practice actually collected.


1. Source and construction

Rates come from Transparency-in-Coverage machine-readable files published by 37 insurer

filings, vintage 2026-Q2-06. Each filing is mined, de-ghosted and rolled to a benchmark cube

at the grain payer × state × billing code × billing class × negotiated type.

The 37 filings are near-redundant snapshots of one corpus rather than disjoint shards: the same

cell appears in as many as 26 filings with an identical median rate to the cent and TIN counts

within 1%. Cells are therefore collapsed across filings (median of the filing medians, max

of the TIN counts), not pooled — pooling would inflate every count roughly 25×.

Per-filing reconciliation: our recomputed median is compared against that filing's own published

benchmark. All 37 reconciled at 100.0% exact across ~21M cells.

2. Quality tiers

TierRuleCells
PUBLISHABLEn_tin ≥ 25, frac_ok ≥ 0.5, frac_penny < 0.2, rate within [0.5, 10]× ASP, real negotiated or fee-schedule type829,646
PROVISIONALn_tin ≥ 10, rate within [0.3, 20]× ASP508,684
SUPPRESSEDimputed (derived/per diem), thin, out-of-band, or unanchored to ASP2,615,117

Every headline figure uses PUBLISHABLE cells only. The suppressed share (66.1%) is higher

than the previous issue's 40.7% because the corpus grew 4× by adding all 37 filings, and the

added cells are disproportionately thin — publishable cells themselves rose from 328,877 to

829,646.

Tail truncation is real and matters. The publishable gate requires the rate to fall within

0.5–10× ASP, so percentiles and the underwater list are computed on a variable clipped at both

ends. Rates outside that band are not errors by definition, but we cannot distinguish a genuine

extreme contract from a unit error at that distance, so they are withheld.

3. Denominator

Rates are expressed as a multiple of ASP (average sales price). Medicare pays ASP + 6%

by statute, i.e. 1.06×, before sequestration; after sequestration the effective figure is about

1.043×. CMS's ODACS survey puts non-340B acquisition cost at about ASP + 2.7% (1.027×).

These three lines are the benchmarks used throughout.

Reading ×ASP as a margin proxy breaks in two known cases: 340B pricing, where acquisition

cost is far below ASP, and drugs in shortage, where spot acquisition can exceed it.

Drugs are withheld from the practice-facing lookup where the ASP denominator is missing,

provisional or under $1.00, or where the code is an oral formulation — the price is real but

the ratio would not be.

4. Known defects corrected in v2.0

four-letter suffix carried by newly licensed originators. 117 brand biologics ($13.4B of

Part B spend — Darzalex Faspro, Vabysmo, Enhertu, Padcev among them) were wrongly excluded

from the headline universe. Corrected to the CMS Q5xxx range, which is the biosimilar

convention; every hyphenated non-Q5 code in this corpus is an originator or antibody-drug

conjugate.

therapeutic one, and J0129 named the self-administered autoinjector rather than the IV code.

the highest-paying insurer in the country. On the rebuilt corpus it is 1.047× with

essentially unchanged drug coverage (733 → 728 drugs). The earlier figure was wrong. Any

v1.4 citation of it is withdrawn.

4b. The headline universe

The flagship share ("drugs carrying 85% of Part B drug spend…") is computed **excluding skin

substitutes**, consistent with every other conclusion-bearing surface. Including them the figure

is 87.1% of $53.4B — the exclusion makes the headline smaller. Reference lines (ASP = 100):

56.5% of spend below 100, 85.0% below 102.7 (acquisition), 92.0% below 104.3, 94.3% below 106.

4c. Newer exhibits and their sources

estimate (n = 77), margin = median contracted index − measured acquisition index. NADAC

refreshes monthly; the subset skews multi-source and is labeled as such.

excluded). Spend-weighted payment-limit trend; the "double squeeze" list = drugs below the

acquisition benchmark with a falling payment limit.

class, cells with ≥25 practices. Modal share is approximate (row grain includes modifiers).

pages carry per-payer tables, ASP history, and — only where measured — margin sections.

snapshot on Clearance refresh · Part B utilization annually.

5. Statistics and their limits

Dispersion. The Same-Drug Spread was previously computed as max ÷ min across insurers in a

market. That estimator rises mechanically with the number of insurers filing — measured on this

corpus it climbs from 1.401× at 6 insurers to 1.937× at 20+, while p90/p10 stays flat

(1.256 → 1.181). Max/min therefore partly measures filing coverage rather than disagreement,

and is reported only as a labelled extremes statistic.

Carrier attribution. 119,260 publishable cells (14.4%) carry no resolvable carrier label.

They are retained in the Index and excluded from all payer-level tables.

Tested and rejected. A "shared pricing engine across nominally independent insurers" signal

did not survive removal of the drug × state main effect (residual correlation median 0.056,

p99 0.859) and is not published as a finding.

Known open questions. The site-of-care matched-pair count has not changed across a 4×

corpus expansion and is being re-derived. The preferred-vs-non-preferred steering result rests

on 19 policies and reverses sign when computed unpaired; it is reported paired, with its n, and

carries no directional claim.

6. What this data cannot tell you

A practice is paid rate × (1 − denial) × collection − acquisition − wastage − prior-auth labor.

This report publishes the first term only. No public dataset supports a drug-level denial

multiplier: CMS and KFF publish payer-level rates with no procedure-code field, and no public

days-to-pay or underpayment file exists at any grain. Administration codes (96365, 96413) are

billed separately and are not in this dataset, so a drug-line ratio is not a profitability

finding on its own.

7. Reproducing this

report_data.json carries every published figure. The corpus is rebuilt by aggregating each

filing to cube grain, collapsing across filings, applying the tier rules above, and re-running

the analysis scripts. Source URLs and their checksums are listed in sources.json.

*Corrections: open an issue against the published dataset, or write to the address on the

report. Errata are recorded in the changelog on the page and in this file.*