The NDC is printed on the drug's package and label, usually near the product name and prefixed with "NDC". To confirm it, look it up in the FDA NDC Directory and check that the listing is current, that the package code matches the package in your hand, and that you are using the package NDC rather than the product NDC.
Where the NDC is printed
US drug packages carry the NDC on the principal display panel of the carton and on the container label, usually with the letters "NDC" in front of it. It is printed in the FDA's 10-digit form with hyphens, for example 0006-3026-02.
The package barcode also contains it: the GS1 GTIN on most US drug packages embeds the 10-digit NDC. Pharmacy and inventory systems read the NDC from that barcode.
Use the NDC of the package that was actually used. A carton that holds several vials can have one NDC on the carton and a different one on each vial; the FDA listing shows how they relate.
How to look one up
If you know the drug but not the code, search the FDA NDC Directory by brand name, generic name, active ingredient or labeler. On Med-Code, each drug, active ingredient and labeler has a page listing every one of its NDCs, and each NDC has its own page with its package NDCs.
If you have a code and want to know what it is, search the code itself. Med-Code accepts it with or without hyphens and in 10- or 11-digit form, and matches both product NDCs and package NDCs.
Four checks before you use it
Is the listing current? Look for the product in the current NDC Directory. Check the marketing end date and listing expiration date; a product whose listing lapsed may be rejected even though packages are still in stock.
Does the package match? The third segment identifies the package size. Make sure the package description in the listing (for example "1 vial in 1 carton, 4 mL") matches what was used.
Is it the package NDC? Claims need the full three-segment package NDC. The two-segment product NDC identifies the formulation only.
Is it in the right format for the claim? Electronic claims need the 11-digit 5-4-2 form, with a leading zero added to the short segment.
When a code can't be found
Check the digits against the package again and try both the 10- and 11-digit forms. A code that is still missing may belong to a product that was never listed, was delisted, or is an unfinished drug (such as a bulk ingredient) that is not in the finished-product directory. The FDA also publishes an NDC excluded list for listings it removed from the main directory.
Questions
Is the NDC on the vial the same as the one on the carton?
Not always. When a carton holds several units, the carton and the individual units can have different package NDCs. Payers generally want the NDC of the package the drug was taken from; check the payer's rule.
Does finding an NDC in the directory mean the drug is approved?
No. Listing is separate from approval. The listing's marketing category shows whether the product was approved under an NDA, ANDA or BLA, or marketed under another category.