What is the National Drug Code?
The National Drug Code (NDC) is a unique, three-segment numeric identifier assigned to prescription drugs and certain over-the-counter (OTC) products marketed in the United States. The NDC is maintained by the U.S. Food and Drug Administration (FDA) and serves as the standard for identifying drugs at the product and package level. NDC identifiers enable accurate identification and tracking of drugs throughout the supply chain, and are used across manufacturing, distribution, reimbursement, and regulatory compliance.
How does the NDC system work?
Because no two NDCs are the same, the code provides a precise way to track drugs across systems such as claims processing, formulary management, rebates, recalls, and pharmacovigilance. Each NDC uniquely identifies:
- The drug manufacturer or labeler, with a labeler code assigned by the FDA. This segment identifies the manufacturer, repackager, or distributor responsible for the drug. Labeler codes can be 4 or 5 digits long.
- The specific product formulation and strength. Product codes are assigned by the labeler, and identify the drug’s specific formulation, strength, dosage form, and route of administration.
- The package size and type. The package code is also assigned by the labeler, and it identifies the package size and type, such as a bottle, blister pack, or vial.
What does an NDC number look like?
An NDC is typically displayed as a 10-digit number, divided into three segments. However, for billing and electronic transactions, it is often converted into an 11-digit format. The 11-digit NDC uses leading zeros to create a standardized 5-4-2 format required for most payer billing systems, particularly for Medicaid and Medicare claims.
- Example 10-digit format: 12345-678-90
- Example 11-digit billing format: 12345-0678-90
How is the NDC different from other drug identifiers?
The NDC is often confused with other drug identifiers, but each serves a different purpose. For example, RxNorm codes (RXCUIs) are often used in EMRs. These are unique, machine-readable identifiers created by the National Library of Medicine to standardize names and properties for clinical drugs. These codes enable interoperability between different pharmacy databases and are updated weekly, often mapping to NDC codes.
HCPCS codes, also known as J-codes and Q-codes, are billing codes commonly used for medical benefit drugs. While HCPCS codes may group multiple products together, NDCs provide the granularity needed for precise pricing, rebate, and access analysis. Many payers will deny claims if a provider’s NDC/HCPCS crosswalk information is incorrect.
How do NDCs impact market access and reimbursement?
For manufacturers and market access teams, NDCs directly influence revenue and access.
Payers often evaluate coverage at the NDC level, particularly when products differ by formulation, strength, or package size. A single brand may have multiple NDCs, each with different coverage, utilization management criteria, or reimbursement rates.
Because rebates, chargebacks, and discounts are frequently calculated at the NDC level, manufacturers must carefully manage NDC portfolios to avoid leakage and ensure contract performance. Many manufacturers also choose to help providers use the correct coding, crosswalk data, and conversion units.
