National drug code

The official FDA format for NDCs separates the 3 segments with dashes.

This is the format in which the NDC must be submitted by labelers since mandatory electronic listing was established in June 2009.

[6] While the NDC is a 10-digit identifier, confusion exists because of a proliferation of different notations and variants.

The Centers for Medicare and Medicaid Services (CMS) had created an 11-digit NDC derivative, which pads the labeler, product, or package code segments of the NDC with leading zeroes wherever they are needed to result in a fixed length 5-4-2 configuration (but always written without dashes).

[8] This format was adopted by data standards selected pursuant to HIPAA regulation, thus other government agencies' lists and databases (such as the UMLS) may contain the 11-digit derivative of the original NDC.

In some applications, the fully expanded 5+4 digit labeler+product code is used as a 9-digit number to identify a product regardless of packaging.