Audit PBM Cost-Plus + Dispensing Fee Claims

By Dylan Sanson, Pharmacist & Pharmacy Manager · Published May 16, 2026 · Updated October 5, 2026

A growing wave of PBM contracts — driven by employer demand for transparency and recent state and federal reforms — has moved away from opaque MAC and AWP-minus pricing toward a cost-plus model: the pharmacy is paid its actual acquisition cost plus a flat professional dispensing fee. On paper, that's a fairer deal for independents. In practice, you only capture that fairness if you audit every claim.

This guide breaks down the new model and shows you exactly how to use NADAC Lookup to verify each reimbursement and catch underpayments before they pile up.

What Does "Cost-Plus + Dispensing Fee" Actually Mean?

Under the new model, your reimbursement is calculated as:

The "acquisition cost" benchmark is typically NADAC — the CMS-published, invoice-based price that updates every Wednesday. The dispensing fee is contract-specific but usually lands in the $9 to $12 range, mirroring the Medicaid professional dispensing fee methodology. For background on how that fee is set and how Medicaid programs use the same structure, see Calculate Reimbursement from NADAC.

Why Do You Still Need to Audit Every Claim?

Even under a transparent cost-plus contract, underpayments happen — and they usually fall into three buckets:

• Stale NADAC reference. The PBM priced your claim against an older NADAC effective date. If the price went up Wednesday and your claim was adjudicated using last week's NADAC, you're underwater on the ingredient cost.
• Wrong NDC mapping. The PBM applied NADAC for a generic equivalent or a different package size instead of the NDC you actually dispensed.
• Missing or reduced dispensing fee. Some plans quietly carve out specialty, 90-day, or 340B claims and pay a lower fee than the contract states.

Each of these is appealable — but only if you spot it. That's where a weekly audit habit pays for itself.

How Do You Audit a Claim in 5 Minutes?

Pull your remittance for any cost-plus contract claim, then walk through these steps:

1. Search the exact NDC dispensed on NADAC Lookup. Using the 11-digit NDC (not just the drug name) ensures you're comparing the same product the PBM should have priced — see how to look up by NDC.
2. Check the effective date. Confirm the NADAC effective date is on or before the fill date on your claim. If your claim used an older NADAC than what was published the prior Wednesday, that's an audit flag.
3. Calculate expected ingredient cost. Multiply NADAC per unit by the quantity dispensed. Compare to the ingredient cost paid on the remittance — any shortfall greater than a rounding penny is recoverable.
4. Add the contracted dispensing fee. Verify the PBM paid the full fee specified in your contract, not a reduced specialty or chain-equivalent rate.
5. Sum and compare. Expected reimbursement = (NADAC × qty) + dispensing fee. If the PBM paid less, file an appeal with the NADAC entry, effective date, and your calculation as supporting evidence.

Worked Example

You dispense 30 tablets of Atorvastatin 20 mg under a cost-plus contract with a $10.50 dispensing fee. NADAC for the NDC on the fill date is $0.0412 per unit. The PBM paid you $1.05 ingredient + $10.50 fee = $11.55 total.

Nineteen cents sounds trivial. Multiply it across hundreds of claims a week on the dozens of high-volume generics that move price most often, and the recoverable revenue is meaningful.

Which Claims Should You Audit First?

You can't audit every claim manually, but you don't need to. The highest-risk claims are the ones where NADAC moved this week — those are most likely to be priced against a stale benchmark. Start your audit there:

• Check the Weekly Movers page every Wednesday after CMS publishes new NADAC data. The top 10 increases are the drugs most likely to be underpaid this week.
• Cross-reference those movers against your dispensing volume. Any drug in both lists deserves an immediate spot-check.
• Pull the matching remittances and run the 5-step audit above.

Make the Audit Automatic with Pro

NADAC Lookup Pro ($29/mo) turns this from a manual task into a routine:

• Save your top-dispensed drugs so they're one click away each Wednesday.
• Price change alerts notify you the moment NADAC moves on a drug you stock — before any claim gets paid against the new number.
• Full 5-year price history makes documenting a trend trivial when you escalate to contract renegotiation.
• Weekly movers email digest delivers the top 10 increases and decreases straight to your inbox every Wednesday morning.

Where Do These Numbers Come From?

NADAC values on this site come straight from the CMS weekly file. Check the primary sources yourself:

• CMS NADAC (National Average Drug Acquisition Cost) dataset on data.medicaid.gov — the weekly file every NADAC price on this site is pulled from.
• CMS Retail Price Survey — how CMS collects pharmacy invoice data and calculates NADAC.
• 42 CFR Part 447, Subpart I — the federal rule requiring Medicaid to pay actual acquisition cost plus a professional dispensing fee.

The Bottom Line

Cost-plus PBM contracts are a real win for independent pharmacies — but only if you treat the contract as a floor, not a ceiling. Audit weekly, document every shortfall, and use the data to push back. The same NADAC numbers that justify your reimbursement also justify your appeals. For broader strategy on bringing this data to the negotiating table, see Using NADAC for PBM Negotiations.