Why Not Data Matrix?

The data-dense symbol can be read successfully from any angle, even if part of it is damaged. So why not use it for small packages?

by Stephen G. Hess, director, packaging technology, Merck & Co.

Many pharmaceutical and biological product manufacturers are interested in using or expanding the use of Data Matrix ECC 200 as an accepted bar code symbology. Data Matrix is a unique two-dimensional symbol initially commercialized approximately 15 years ago. It is now available in the public domain. Data Matrix had originally been demonstrated in the defense industry and for on-part marking and coding. According to suppliers, Data Matrix has also been used in pharmaceutical applications for about 10 years.

Data Matrix is now poised to expand to applications throughout the healthcare sector. It offers flexibility not seen in other symbols, especially in terms of symbol size and shape. Data Matrix can be square or rectangular to best fit the space available on your product packaging. It is also scalable from 1 mil up to a 14-in. square, although a more-typical size would be much less than one square inch. In fact, a typical Data Matrix symbol that could encode National Drug Code (NDC), lot number, and expiry date could be approximately 5�16-in. square, including the quiet area.

Data Matrix ECC 200 symbology has built-in Reed-Solomon error correction that improves the robustness, speed, and accuracy of reads. Such robustness allows the symbol to be read even when sections of the code are missing. Compared with other symbols, Data Matrix is less sensitive to imperfect print quality and can be read from a variety of angles. It does not require orientation, as do some other symbologies. One of its biggest advantages is that the symbol is one of the most space-efficient codes available. This is especially important for placement on small pharmaceutical or medical device products and packages. Data Matrix can fit where many other codes simply cannot. Another advantage of the symbol is that many current printing technologies are already able to print it.

One of the biggest perceived weaknesses of Data Matrix has been the inability to inexpensively and universally read this symbol. This may have been the case in the past, since inexpensive laser-based bar code scanners cannot read Data Matrix. However, with the recent proliferation of low- cost two-dimensional imagers in the field, this is no longer true. These imagers are now approaching the cost of laser-based scanners. Their use is projected to grow rapidly. Any end-user currently evaluating bar code reading technology upgrades should consider the use of imagers or scanners that can read linear as well as two-dimensional bar codes.

There is even more hope that Data Matrix will be commonly employed in healthcare coding. The Uniform Code Council�s (UCC) Physical Technical Requirements Group recently met and evaluated a change request to add Data Matrix to its stable of approved symbols. That change request was accepted, so work will now begin to establish application guidelines.

We heartily applaud the UCC�s efforts, as this is a positive step for both manufacturers and end-users that wish to use the UCC data structure on small components and packages.

When pharmaceutical manufacturers discuss desired uses for Data Matrix, they most often mention NDC encoding, production lot numbering, product expiration dating, product serial numbering, and product manufacturing dating.

With the limited real estate required for Data Matrix, many of these applications may become possible.   

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