Choosing the Ideal Automation Solution for Your Clinical Instrument – Lasers or Imagers?

Maybe you’re part of a development team for a clinical analyzer or lab automation system and it falls to you to design the specimen traceability sub-system for your instrument. Seems easy enough, right? But what kind of automation technology do you choose – a laser-based or an image-based system? 

Both laser- and image-based technology has its place in life sciences applications. Perhaps the first and broadest assessment to make is whether your project involves decoding 2D symbols (such as Data Matrix or Aztec codes) like those found on reagent or control vessels or on rack background labels. Reading any 2D symbol necessitates image-based technology. The reason is that laser-based readers illuminate only a very thin strip of a barcode with their linear laser beams and therefore cannot  » see » the entire area necessary to decode a 2D symbol. For clinical applications requiring 2D code-reading, an imager such as Microscan’s MS-2D Engine might be the go-to product. 

Another criterion to consider is whether you need to retain an image of the barcode in your system – if this is the case, the decision to use a barcode imager is clear. Why retain an image? Some clinical customers like to keep images of their barcodes as an extra measure of traceability, and to help service technicians troubleshoot cases where specimen labels cannot be decoded. Others jump-start the billing process by using an image of the specimen label at  » check-in » to demonstrate that a test ordered by the care provider has been started. 

Other criteria that might determine the need for an image-based product is whether or not additional tasks beyond decoding are required – for example cap absence or presence, cap color, tube measurement, or liquid fill level. These tasks are typical of applications where inspection is needed before sending a sample tube into a test. If, for example, the tube cap is present and an automated aspirator needle or aliquoter is next in line, detecting cap presence would allow the system to bypass the aspirator step until the specimen tube is de-capped, perhaps placing that tube in an exception rack. Or, if the cap color indicates that the sample is not the appropriate type for the test, or if the tube fill level indicates that the amount of sample is insufficient for the test, the tube can be similarly managed as an exception.  Machine vision smart cameras such as Microscan’s Vision MINI are ideal for this type of application. 

So when are laser-based readers appropriate? Generally speaking, when the project involves decoding a linear (or 1D) barcode, lasers have a couple of distinct advantages. First, the decode speed of lasers is typically much faster than that of imagers because laser-based decodes are nearly instantaneous, whereas imagers must first capture an image and post-process the image to decode a barcode. While an imager might capture and decode a specimen label 20-50 times per second, a laser barcode reader can decode in the neighborhood of 1000 times per second. So for high-speed applications such as a rotary tube-handling system or in an X-Y architecture where a technician will push a rack of specimen tubes into a loading lane, lasers provide a clear speed advantage. Another advantage of laser-based readers includes scan distance and depth of field. Generally speaking, lasers are able to decode over a greater range of distances, close- to long-range. Microscan’s MS-3 Barcode Scanner is a great choice for a compact laser-based reader and has excellent scan width to handle 100mm clinical sample barcodes at a relatively close stance, which helps keep the instrument footprint to a minimum. 

In summary, if you need to decode 2D symbols, retain label images, or perform machine vision inspection tasks, reach for an image-based system. If you need to optimize decode speed and scan distance for 1D codes, a laser-based product is the best choice. With over 30 years serving as the #1 brand of embedded barcode readers for clinical and life science applications, Microscan’s applications team is standing by to help you make the optimal choice for your project. 

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