Sponsored: How To Properly Define GTINs For Your NDCs

Image showing relationships of define GTINs
Packaging Hierarchy. Drawing by Omega Design

RxTrace readers are well aware that the deadline is this November 27 for applying unique serial numbers within GS1 DataMatrix 2D barcodes to prescription drugs distributed in the United States under the Drug Supply Chain Security Act (DSCSA).  Once that happens, most prescription drugs entering the U.S. supply chain will be identified by 14-digit GS1 Global Trade Item Numbers (GTIN-14) for the first time (see “Anatomy of a GTIN”).  That’s because, you can’t fit the drug’s National Drug Code (NDC) along with the serial number, lot number and expiration date into a data matrix barcode, as required by the law, without first encoding it into a GTIN-14 (see “Anatomy Of The National Drug Code”, and “Depicting An NDC Within A GTIN”).  This fact forces companies to encode their NDCs into GTIN-14s, many for the first time.

This will be a momentous step which opens the door to a widespread shift into a more appropriate usage of the NDC.  Once companies define a GS1 GTIN-14 for all their drugs, they can begin using a related but distinct GTIN-14 to identify their homogenous cases (and other groupings) and they can stop using an NDC for that purpose.  The net effect of this will be to reduce confusion in the supply chain, and therefore reduce errors.

It all has to do with a historical use of the “Package Code” field of the NDC (sometimes referred to as the “Pack Size”) by some companies for the identification of groupings.  Even worse, many companies put the same NDC on their cases as they do on the units inside the case!  Now, these practices can—and should—be abandoned in favor of using the “Indicator Digit” of the GTIN-14 instead.  As changes are being made to conform with the DSCSA, companies should go further and carefully review how they define their GTINs to identify groupings of their drug products.  Odds are, changes will be necessary somewhere across their family of products.

These two sub-strings—the NDC’s “Package Code” and the GTIN-14’s “Indicator Digit”—have similar but distinctive purposes.  Let’s review each sub-string.


The “Package Code” sub-string is the last of the three sequential parts of the definition of the NDC, the identifier assigned to each type of packaging for each drug marketed in the United States.  The other two components of the NDC are defined as the “Labeler Code”, which identifies the company that has applied for, or owns the marketing authorization for the drug, and the “Product Code”, which identifies exactly which drug product the NDC is for.  The “Package Code” (or “Package Size”) is the 9th and 10th, or just the 10th digit in the 10-digit NDC code.  (For a more detailed explanation of the NDC, including how to determine whether your “Package Size” sub-string is one or two digits long, see “Anatomy Of The National Drug Code”.)

Because the NDC is the only identifier for drugs recognized by the FDA, some companies historically used the “Package Code” sub-string of the NDC to indicate both the package size for a single saleable unit, and for groupings of the saleable unit.  A “grouping” is a collection of saleable units of the same product (or a collection of lower-order groupings) that are bound together in some way.  Common “groupings” are a “bundle”, a homogeneous case, a homogeneous pallet, etc. 

Using the NDC’s “Package Code” sub-string to indicate both the different sizes of saleable units AND for different groupings of those products introduces complications.  Unfortunately if your “Package Code” is only one digit long, you quickly ran out of values.  It also required additional registration of groupings with the FDA since each grouping of a given pack size led to a different NDC.

The only time it is now appropriate for you to use the NDC’s “Package Code” to define a grouping is if that grouping is itself a saleable item.  That is, if you expect companies to order and stock a particular grouping and dispense or sell it without breaking it down.  Those items should be assigned their own unique NDC by reserving a unique “Package Code” value for them.

“Package Code” “0” (or “00” for NDCs that have two-digit “Package Codes”) should be reserved for a unit-of-use (sometimes referred to as a unit dose) of your drug.  A unit-of-use will never be sold in the supply chain, so it will rarely be encoded into a barcode (some companies are putting a tiny barcode on the back of unit dose blisters of some products for hospital bedside scanning).  But once you create the unit-of-use NDC, it can be used by dispensers to indicate a unit-of-use of your drug in healthcare claims processes.  If you don’t define a unit-of-use “Package Code” for a given drug, then healthcare claims only have your saleable package as an NDC for submission, and that might mean many doses.  When the patient received only one dose, using that saleable pack NDC must be really confusing to the claims processor.


The GTIN-14 identifier is composed of multiple sub-strings.  The first digit is known as the “Indicator Digit”—the first sub-string—(for the complete explanation of the parts of a GTIN-14, see “Anatomy of a GTIN”).  This special digit is used to differentiate various groupings of the saleable package.  That is, the Indicator Digit (ID) can theoretically differentiate up to 10 different groupings of the GTIN (represented in the remaining 13 digits)—except that IDs ‘0’ and ‘9’ are special.  ID ‘0’ indicates the individual saleable unit of the product, to use a term defined in the DSCSA.  ID ‘9’ is reserved for products that have variable measurements at the point of sale, and so that value is not used for healthcare products.  ID ‘1’ through ‘8’ are available to indicate different homogeneous groupings of the product. 

GS1 intentionally does not define exactly which type of grouping is identified by each ID, but leaves that decision up to each manufacturer.  That’s because there are well more than just 8 different potential kinds of groupings when you consider every possible kind of product.  But, any single product is unlikely to have more than 8 different groupings, so it is up to each manufacturer to define which kind of grouping is referenced by each ID.

Interestingly, the GS1 General Specification does not discuss the purpose or meaning of a “0” Indicator Digit, but the GS1 US document “An Introduction To The Global Trade Item Number (GTIN)” does.  Surprisingly, the GS1 US DSCSA Guidance document version 1.2 also does not discuss the purpose of a “0” Indicator digit.


The use of the NDC “Package Code” digit(s) to identify groupings of a given drug product is a bad idea because it results in unnecessary confusion and complexity.  A single NDC should identify a particular drug and it’s saleable package.  Most companies correctly use the “Package Code” field of the NDC to identify different individual saleable package sizes of the identical drug product.  For example, Package Code ‘0’ might be assigned as the unit-of-use as explained above (which may or may not be contained in an actual “Package”).  Package Code ‘1’ may be assigned to a 30-count bottle of the drug in pill form.  Package Codes ‘2’ and ‘3’ might then be assigned to a 60-count and 90-count bottles respectively. 

When a company goes further than that by extending the “Package Code” field of the NDC to indicate groupings of multiple saleable packages, watch what happens.  For example, the same manufacturer above might use Package Code ‘4’ to indicate a bundle grouping of 6, 30-count bottles, and Package Code ‘5’ to indicate a bundle grouping of 6, 60-count bottles, and Package Code ‘6’ to indicate a bundle grouping of 6, 90-count bottles.  “Package Code” values of 7 through 9 might be used to identify case groupings of each 30-count, 60-count, 90-count saleable pack respectively.  Using a hypothetical product, here is what you end up with (Notice that the NDC “Package Code” is in red):


30-Count Bottle

60-Count Bottle

90-Count Bottle

NDC on the Bottle

11111 0001 1

11111 0001 2

11111 0001 3

NDC on bundle of
6 Bottles

11111 0001 4

11111 0001 5

11111 0001 6

NDC on the case
of 4 bundles (24 Bottles)

11111 0001 7

11111 0001 8

11111 0001 9


That results in 10 distinct NDCs that have to be registered with the FDA for one drug (the unit-of-use NDC, plus 3 bottle NDCs, plus 6 grouping NDCs).  Fortunately, most companies don’t go that far.  But unfortunately, some companies just put the same GTIN-14 on their cases as they are now putting on the saleable package inside the case.  This is an incorrect application of GS1 standards.

Now watch what happens when we use the NDC’s “Package Code” field strictly for defining the saleable packages, and the GTIN-14’s “Indicator Digit” for differentiating the saleable units from their higher-order groupings.  This approach follows GS1’s GTIN allocation rules for healthcare.  You only need the NDC’s “Package Code” field to differentiate the various saleable packages made for a given drug.  Then, to identify the bundle and case groupings in the example, use the Indicator Digit in the GTIN-14s that are associated with each product.  Here is what you might end up with (Notice that the “Package Code” of the NDC encoded within the GTINs are in red, the GTIN Indicator Digits are in blue and “x” indicates the GS1 GTIN check digit).


30-Count Bottle

60-Count Bottle

90-Count Bottle

NDC on the Bottle

11111 0001 1

11111 0001 2

11111 0001 3

GTIN-14 on the Bottle
(the saleable package)

0 03 11111 0001 1x

0 03 11111 0001 2x

0 03 11111 0001 3x

GTIN-14 on the bundle
of 6 Bottles

1 03 11111 0001 1x

1 03 11111 0001 2x

1 03 11111 0001 3x

GTIN-14 on the case
of 4 bundles
(24 Bottles)

2 03 11111 0001 1x

2 03 11111 0001 2x

2 03 11111 0001 3x


This approach results in only 4 NDCs registered with the FDA (the unit-of-use NDC, and 3 bottle NDCs).  The six GTIN-14s do not need to be registered with the FDA or with GS1.  The manufacturer defines these on their own.  There are plenty of Indicator Digits left over to be used for additional groupings of this product, if desired.


Now think of what the wholesale distributor would see in each of these two approaches.  When they scan the barcode on a case of product in the NDC-only approach, they get an NDC that identifies the grouping.  Which saleable pack is inside?  Hard to say without doing a look up in a table. 

In the GTIN Indicator Digit approach, the NDC of the saleable package is always encoded within the GTINs used at each level, so it’s easy to tell which saleable packs are inside the scanned grouping.  And the Indicator Digit is at least distinct between the various groupings of that product.  Admittedly, since GS1 does not standardize the assignment of Indicator Digits, a lookup may still be necessary, but only to determine the quantity of the saleable units inside.  An identifier/containment table like this is an important part of the master data that the Healthcare Distribution Alliance (HDA) expects to include in their Origin master data service later this year (except they will include a lot more data) (see “Dawn of HDA’s Origin, The Key to DSCSA Compliance”).


You can learn more about pharma serialization and what other companies are thinking and doing with their NDCs and GTINs in response to the DSCSA and other laws around the world by attending the Pharmaceutical Traceability Forum in San Diego on May 22-25.  It’s part of IQPC’s Pharma Logistics Week, an event where four pharma supply chain conferences are being held in the same location.  When you register for one of those events they allow you to jump around to attend sessions in all four.  That’s a real deal.  The four co-located events are:

This is an incredible idea because it allows attendees to maximize their investment in time, travel and money.  Those facing the pharma serialization regulations will want to register for the Pharma Traceability Forum, but they can sample sessions in the other three events whenever something pertinent to their needs is available.  I suggest they stay aware of the agendas for the Pharmaceutical Packaging and Labeling Forum and the Cold Chain GDP & Temperature Management Logistics Global Forum as well.  Even if you pick up just one session in each of those, you have gain immeasurably by the co-location and the ability to bounce between programs without extra charge.

Take the whole team.  IQPC has group discounts starting at only two registrants from the same company, and up to 30% off for groups of six to nine.  You owe it to yourself to download the agenda and venue information here.  Register before March 17, 2017 and save $300!