Which purchase invoices count in a pharmacy audit?

Invoices and records to keep

• Invoices from your primary wholesaler, with the NDC, quantity and date for each line.
• Invoices from secondary suppliers. Check that each supplier is properly licensed and that your PBM contracts accept their invoices.
• Credit memos and return records, which reduce the quantity you can count as purchased.
• Records of transfers between pharmacies, including stores under the same owner, showing what moved, when and in what quantity.
• Statements or purchase histories from suppliers, which can help if an individual invoice is missing.

Organize invoices so they can be found by NDC and date

Auditors work drug by drug and period by period. Keep invoices, or a purchase history export, that can be searched by NDC and date, so you can show what was bought for any audit period. Where you buy the same drug in different pack sizes or from different manufacturers, keep a note of which NDCs are equivalent. Our guide to NDC reconciliation explains how equivalent NDCs and pack sizes are matched.

Common gaps auditors find

• Purchases from a supplier whose invoices the PBM does not accept.
• Transfers between pharmacies with no written record.
• Returns and credits that were not subtracted.
• Products bought under one NDC and billed under another, with no explanation of the equivalence.

Set up a simple invoice routine

A short routine keeps invoices ready for any audit period. Download or file every supplier invoice and credit memo as it arrives, in one place, named by supplier and date. Once a month, export the purchase history from each supplier and keep it with the invoices, so a missing paper copy can be replaced quickly. Record every transfer between pharmacies on a standard form signed by both stores. Keep a running list of the NDCs you treat as equivalent for each drug, with the pack sizes, so the connection can be explained when an auditor compares purchases with claims. If you change suppliers, keep the old supplier’s invoices and purchase history for as long as your contracts and the applicable rules require.

Check purchases against dispensing before an audit

You do not need to wait for an audit notice to see how your purchases compare with your claims. Pick a few high-volume or high-cost drugs, total the quantity purchased over a recent period from all suppliers, subtract returns, adjust for transfers, and compare the result with the quantity dispensed. A gap is not automatically a problem, because equivalent NDCs and pack sizes are often the explanation, but checking early gives you time to find missing invoices or records.

Frequently asked questions