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UDI Labeling: Pitfalls and Best Practices, Part 2 of 2


UDI labeling can be a challenge for medical device companies as they work towards compliance by the deadline. This post is part two in a two part series to help device manufacturers avoid common mistakes and implement best practices for UDI labeling. You can read part one here.

Barcode size
The larger a barcode is, the better the chance of fast and accurate scanning. For the GS1-128 barcode, GS1 recommends the following values for the x-dimension (X-dimension is the width of the symbol’s thinnest bar also known as the narrow bar).

Min: 0.495mm
Recommended: 0.495mm
Max: 1.016mm

The recommended height for the linear barcode is 32mm.

For the GS1-DataMatrix barcode, the recommendation for the x-dimension (size of the smallest dot in the code) is 0.300mm/0.0118 inch (0.2mm for direct marking of small medical devices).

These values are guidelines. In reality, you may not have enough space and the barcodes will be smaller than these requirements. If the print quality (contrast between black and white lines/dots) is good, a decent scanner will still be able to properly read the barcode.

Common mistake: design for the wrong dpi
With some label design approaches, you risk creating a label that does not match the printer’s correct dots per inch resolution (dpi). This can happen when creating a PDF or when hard-coding a printer template using the printer’s command language.

Designers usually optimize PDFs for high resolution laser printers 600dpi/1200dpi/2400dpi. When you print PDFs on a label printer with 203dpi or 300dpi, the very narrow bars in the barcode cannot be printed at the proper resolution, making the barcode difficult to read or even unreadable.

Similarly, when you program using printer commands, you need to have the DPI and barcode dimensions in mind.

Best practice: Use a label management solution (LMS) that includes a label design application that makes it easy for business users to design compliant UDI labels. You do not need to worry about the printer model and resolution at design time as the label templates are universal. The NiceLabel LMS optimizes the print stream dynamically for the target printer just before printing, which ensures the best printing quality and maximum performance.

Common Mistake: The barcode prints over the edge of the label.
This error is common when label templates are programmed using the printer’s command language. Barcodes can stretch over the edge simply because a value changes from numeric to alphanumeric. In the example below, changing the LOT value from 0001 to A001 extends the barcode.
UDI Barcode
You can avoid this problem by printing labels using an LMS. With NiceLabel, you can set the barcode to always fit into the designated area.

NiceLabel is a leading developer of label and marking productivity software solutions that help companies reduce complexity and mitigate risk while meeting compliance requirements and increasing productivity, quality and agility. To learn more about UDI compliant labeling visit

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