Your barcode awareness may begin and end with the "beep" youhear. Yet, you know that data has been collected quickly, quietly andaccurately. From the grocery store to the microwell plate in your lab, barcodesare ever-present. But our knowledge of them is often superficial, and as aresult, we don't fully enjoy their benefits. Their critical role in drugdiscovery suggests knowing how they work makes us more productive users of thetechnology.
Our purpose here is to provide a technical overview oflinear and two-dimensional (2D) symbologies (barcode languages), understand theprint characteristics that impact scanability, offer training suggestions fornew users and confirm how barcode scanning reduces errors and increasesthroughput in today's drug discovery lab.
How do barcodes work?
The basic principle couldn't be simpler: Light is reflectedin different amounts by different colored surfaces. The black barcode barsreflect less light than the white spaces. Regardless of the device employed(handheld wand, moving-beam laser, CCD), every barcode scanner contains asource of light and a method for receiving the light reflected from a scan.
The width of each bar or space being scanned determines howlong the light is reflected into the scanner. Predefined width patterns(typically just different arrangements of narrow and wide bars and spaces) areused to represent the data encoded. Linear barcodes have been thought of as aprinted version of the Morse code, with narrow bars and spaces representingdots, and wide ones representing dashes. The scanner then uses a decodealgorithm to figure out what each specific series of bars means. Most linearscanners are capable of decoding numerous barcode languages or symbologies withoutuser intervention, so the user need not know what type of barcode is beingscanned.
What about 2D codes?
Driven by the desire to encode more information in lessspace, 2D symbologies were born. They operate on a similar principle to basicbarcodes, but require more sophisticated reading devices, called imagers. Thesescanners use vision-based technology to take a picture of the symbol andinstantaneously decode it, regardless of orientation. Some of these imagerswill also decode basic barcodes as well.
Making barcodes workfor you
Like all technologies, there are some common issues that mayarise when implementing or enhancing a barcode system. These unforeseenproblems can easily be overcome with careful planning and training.
Plates, slides, tubes and vials all have limited real estateto accommodate a label, which is a common barcode constraint within a drugdiscovery facility. Before you try to design a label that encodes the date,technician ID, sample origin, study name, patient ID, medical record number,Social Security number and your favorite color, consider using a unique numberthat simply provides access to the database instead. Shorter messages areeasier to decode and label costs will be lower.
Barcode scanners need to be able to easily differentiatebetween bars and spaces, which is why black and white is the preferred colorscheme. Some barcode enthusiasts have been heard to say, "Black and white means'read' all over." Hokey, but accurate. If this is of concern, preprinted labelsfrom an experienced vendor offer the best assurance of symbol contrast.
If preprinted labels are not an option, the best technologyfor on-demand barcode production is thermal transfer printing. But all thermaltransfer printers are not created equal. 600-dpi models with very tight printtolerances are especially useful in drug discovery, where plates, slides andtubes offer little space for labeling. Matching the label stock with the rightribbon is also critical to scanning success. It's important to work with avendor with extensive laboratory expertise to avoid common printing pitfalls.An inexpensive label quickly becomes very costly when it has fallen off, orworse, is misread.
The array of scanners available today can be overwhelming,but don't let that allow you to lose sight of how scanning will take place inyour lab. Look at all the real-life scenarios and select scanners accordingly.If linear barcodes are the only type you use, there is no need for imagereaders. If you use a mix of linear and 2D barcodes, there are more advanced(and costly) scanners available that will read both. Most laboratory equipmentcomes with scanners already installed, so the primary concern should be whereadditional, human-based scanning will occur. In situations where people willdirectly interact with technology, the "try-before-you-buy" approach makessense. Make sure you test the scanner with the same labels that will be routinelyused in your application.
The automated lab is quickly becoming the de-facto standard. In drug discoverylabs, this often includes print-and-apply label applicators specificallydesigned to work in conjunction with automated plate handling equipment. On amore basic level, there are simple print-and-apply systems designed forcylindrical surfaces that can also apply labels to flat surfaces, so bothmicrowell plates and tubes can be labeled with the same device.
If all this makes your head spin, there's an even simplersolution: Outsource your labeling entirely. There are now firms that offer prelabeledlabware on a service bureau basis. The user specifies a container and sequence,and the firm provides the labware—tubes, plates, slides—with those itemsalready labeled and packaged sequentially. Permanent ID for especially harshenvironments is even available via ceramic labels fired onto glassware.
One of the great features of barcode technology is itsease-of-use. There are three major types of scanning devices in use today, andtraining couldn't be simpler:
- Contact wands: Holding the scanner as you would a pen, drawan imaginary line through the linear barcode symbol, starting on the whitemargin (called the quiet zone) at one end of the symbol and ending on the whitemargin at the opposite end. Don't allow the imaginary line to leave the symboluntil the pass is complete. Barcodes are bidirectional, so they can be scannedleft-to-right or right-to-left. Scanning speed can be anywhere from two to 20inches per second.
- Laser scanners: Simply pull the trigger and shoot. Based on the printing characteristics of the symbol, adjustments in the distance from the scanner to the barcode may need to be made to find the sweet spot that produces the best results.
- CCDs: These simple scanners take a flash photo of the entire symbol. The user need only touch the barcode with the scanner and a successful read will occur.
What's next inautomatic identification for the drug discovery lab?
No discussion of automatic identification and barcodes wouldbe complete without a mention of radio frequency identification (RFID). Thetechnology offers some compelling capabilities. RFID uses radio waves tocommunicate between a reader and a tagged item. The tag responds with a signalthat is modulated with information stored within it.
One attractive feature of RFID is that a line-of-sight isnot required for reading. In other words, the object to be scanned does notneed to be optically visible to the reader. The tag can be in an unopenedcarton or stored high on an inaccessible shelf. Another differentiating featureof RFID is its ability to change the information encoded in the chip from adistance. With read/write chips, information can be updated and changedremotely, so the identification of the item is accurate in real time.
The added expense of an RFID infrastructure has proven to bedifficult for many lab environments to justify. While barcode scanning requiresa relatively small investment in proven technology, RFID is still new enoughthat costs are high. But there is no question that as demand increases,competition will intensify and prices will fall. For today, it might be prudentto view RFID as a possible future enhancement to the barcode system, ratherthan an immediate replacement for it.
How will barcodesimprove my lab?
Generally speaking, when a job is done quickly, accuracysuffers. Barcodes have exploded in the lab because they don't require thattrade-off. With a high-quality barcode label, a working scanner and a trainedoperator, data collection can happen at lightning speeds with 100-percentaccuracy. There are few places where this is more important than in the area ofpharmaceutical research and drug discovery. Researchers, doctors, medicalprofessionals, clinicians and patients all have a vested interest in labaccuracy, and new regulatory pressures reward facilities that produce resultseffectively and efficiently.
There is no technology that represents a larger return oninvestment than barcodes. But the productivity improvements aren't automatic, anddeveloping a best-practices approach to using the technology is certainlyimportant. By following the guidance above and partnering with experiencedvendors, pitfalls can be avoided, budgets can be adhered to and data can becollected quickly and without error. Most importantly, critical resultsaffecting patient outcomes will be based on data that is reliable and accurate.And that's good for all of us.