Government Health Program Intelligence
NADAC — the National Average Drug Acquisition Cost — is a survey published by the Centers for Medicare & Medicaid Services that estimates what retail pharmacies actually pay to acquire a drug product. It is used as a reference point: comparing what a payer reimbursed against what the product cost to acquire shows where reimbursement sits relative to a national average. It is a benchmark, not a price ceiling and not a rule.
Published 28 July 2026 · Last updated 30 July 2026
NADAC is built from invoice data collected from retail community pharmacies. CMS publishes it as a per-unit cost by 11-digit National Drug Code, updated weekly, with an archive of prior files.
Two properties make it useful as a benchmark. It is acquisition-based — derived from what pharmacies paid, not from a list price like AWP or WAC that no one transacts at. And it is public — anyone can download the same file and reproduce the same comparison, which matters when a finding has to survive review by the party it concerns.
Most analytical errors involving NADAC come from treating it as something it is not.
The comparison joins reimbursement records to NADAC on the 11-digit NDC for the same period, after normalizing both sides to the same unit basis:
variance % = ((submitted unit price − NADAC unit price) ÷ NADAC unit price) × 100
On the reimbursement side, the two public files that support this at scale are Medicaid State Drug Utilization Data, published quarterly at state level, and the CMS Quarterly Prescription Drug Plan Formulary, Pharmacy Network, and Pricing Information Files, published quarterly at plan level. Both carry a vintage, and a benchmark comparison is only interpretable when the reimbursement period and the NADAC file are aligned to each other.
| Error | What it looks like | Control |
|---|---|---|
| Unit-basis mismatch | A per-millilitre price compared to a per-unit price, producing an enormous apparent multiple | Normalize both sides to the same basis before comparing; flag any record where the basis differs |
| NDC format drift | 10-digit and 11-digit codes, hyphenated and unhyphenated, failing to join or joining to the wrong product | Normalize to 11-digit 5-4-2 and validate against the FDA NDC Directory |
| Temporal misalignment | A current NADAC file compared to a reimbursement quarter from a year earlier | Align the NADAC file to the reporting quarter under analysis |
| Cross-formulation comparison | Tablet, solution and suspension forms of the same molecule mixed into one comparison | Compare within formulation; suppress or separately label cross-form results |
Each of these produces a number that looks like a large finding and is an artifact. Any analysis that cannot state how it handles all four should be treated with caution — including this one, which is why the controls are named rather than implied.
A material variance identifies a record worth validating against the payer's own claims data. That is the whole of the claim. It does not establish that a payment was improper, that any party acted wrongly, or that an amount is recoverable. Those are determinations for the agency, payer, or counsel that holds the underlying data and the authority to act on it.
NADAC, Medicaid State Drug Utilization Data, and the Medicare Part D Prescriber Public Use File are published by CMS and are free to download. The FDA NDC Directory is published by the Food and Drug Administration. Every figure Adrastia produces comes from these files, which is what allows a client to check the work rather than take it on trust.