According to the Institute for Safe Medications Practices, the FDA’s bar-code rule ended a long time standoff between manufacturers and hospitals. Basically, manufacturers were reluctant to invest in systems to produce bar coded unit-dose packages if hospitals didn’t have bedside scanning equipment. On the other hand, hospitals did not want to invest in bedside scanning systems unless most medications were available in bar coded unit doses.1 However, April 26, 2006, the date the bar-code rule came into effect, marked the end of this deadlock since the ruling now requires printing of bar codes on all prescription products and selected OTC items used in hospitals.
Fulfilling this FDA bar code printing requirement represents a two part challenge for manufacturers. First, manufacturers must ensure that their printed bar codes consistently function for the purpose that they are intended for. That is, their bar codes must readily and accurately provide the information that has been encoded within them.
In the past, nurses and pharmacists have reported that some products with bar codes are difficult or impossible to scan.2 Of course this could be a result of hospitals and/or healthcare facilities not using high quality scanners. But even if this were the case, manufacturers have to ensure that their printed bar codes are readable even under less than ideal circumstances. Therefore, ensuring that bar codes are consistently printed in the highest quality possible is a must.
How can manufacturers ensure the quality of their bar codes? According to the FDA, their best bet is to turn to a third party. For example, the FDA’s Guidance for Industry, Bar Code Label Requirements Questions and Answers, dated April 2006, answer #16 states that the FDA has no intention of issuing any guidance regarding bar code quality, such as size, symbol quality, symbol grade and reflectance because they believe that there are sufficient documents and standards issued by third parties to address such bar code quality and standard matters.3
What would a third party tell a manufacturer? They would tell them that once a bar code is printed, this bar code should be tested. In the industry, this testing is commonly referred to as bar code grading.
A quick search will turn up many companies that offer bar code grading systems, but few can say that they offer “true” bar code grading. To assign grades to bar codes, the grading system must be calibrated to the National Institute of Standards & Technology bar code values. Secondly, the inspected bar codes must be graded according to the ISO/IEC standards. This is where many companies fall short because their grading systems simply don’t comply with these requirements. The reason for this varies, but often companies simply lack the expertise and/or control over the particular features of their systems.
Calibrating a vision system is a difficult process because it has to be independent of system lighting and setup. To calibrate a system for a particular type of bar code, the system must be presented a NIST standards card for the particular type of printed bar code to be graded. The system reads the test bar code, then it grades the test bar code, and finally, the system assigns a grade value to it. This grade value is then compared to the test grade value of the bar code. The closer the obtained value is to the test value, the better and the more accurate the results of the system will be.
For example, if a standard’s card value for a printed RSS-14 bar code states that its reflectance value is 80%, the system should also be able to assign a reflectance value of 80% to this bar code. It is important to note that the original 80% reflectance value assigned to the RSS-14 bar code, was generated under “ideal” laboratory conditions (ie., ideal lighting, substrate and etc.). However, grading systems must grade bar codes under less than “ideal” conditions so there needs to be a correlation between the obtained results and the reference values.
Correlating grading results between the reference bar code and inspected codes possess yet another challenge; bar codes are printed on varying substrates, and these substrates directly affect the values of the parameters. These parameters’ values must then be correlated as accurately as possible to the values that are obtained from the NIST reference for that bar code. Therefore, control over external factors, coupled with precise correlation between the values is essential for accurate system calibration.
With respect to the ISO/IEC standards for linear and 2-D bar code grading, these standards refer to how the systems should be constructed and what types of analyses the bar codes should undergo. According to the standards, it is recommended that linear bar codes undergo a ten horizontal scan process of eight quality parameters. In addition, verification of quiet zones should also be carried out. Each scan process generates an overall scan reflectance profile. These profiles are then averaged to generate a value that becomes the overall grade for the bar code. A slightly different process exists for 2-D bar codes. However, it is important to note, that not all grading solutions currently on the market measure all of these eight parameters, and if they are not, they certainly cannot guarantee bar code readability by end-users.
In the end, providing systems that carry out bar code grading is easy; providing systems that carry out “true” bar code grading is not so easy.
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