NDCs are assigned by the Federal Drug Administration (FDA) and serve as universal product identifiers for human drugs. These codes indicate the product (FDA Product Code), the manufacturer or packager (FDA Labeler Code), and the packaging (e.g. 5 dose vial).
The format of these codes varies within each component (4-4-2, 5-3-2, or 5-4-1). The combinations of these components have 10 numbers.
In many uses, these 3 components are normalized to a consistent pattern (5-4-2) with dashes between components. A component is left-padded with zero (0) to adjust the size. These more familiar codes are labeled NDC11 in these pages.
In most cases, there are separate NDCs for the Unit of Use (primary) and Unit of Sale (secondary) packaging of a vaccine. That is, the syringe that contains the vaccine has one NDC and the carton of 10 syringes has a different NDC.
Primary package: The container (i.e. vial or syringe) that holds the vaccine. This is generally referred to as the vaccine’s Unit of Use.
Secondary package: The container or packaging that holds the primary packaging. For example, a carton of 5 syringes. This is generally referred to as Unit of Sale or a saleable unit.
The NDC linker ID allows identification of correspondent NDC unit of use and NDC unit of sale through NDC outer ID and NDC inner ID.