Standardization and use of colour for labelling of injectable drugs

Medication errors are one of the most common causes of patient injuries in healthcare systems. Poor labelling has been identified as a contributing factor of medication errors, particularly for those involving injectable drugs. Colour coding and colour differentiation are two major techniques being used on labels to aid drug identification. However, neither approach has been scientifically proven to minimize the occurrence of or harm from medication errors. This thesis investigates potential effects of different approaches for using colour on standardized labels on the task of identifying a specific drug from a storage area via a controlled experiment involving human users. Three different ways of using colour were compared: labels where only black, white and grey are used labels where a unique colour scheme adopted from an existing manufacturer's label is applied to each drug colour coded labels based on the product's strength level within the product line. In addition to the drug identification task under normal conditions, the different approaches for using colour were compared in terms of the accuracy and the amount of time to complete the tasks under two conditions designed to induce human error. These conditions simulated stocking errors involving the misplacement of a wrong drug with a look-alike, sound-alike name and also with a look-alike label as the correct drug at the place where the correct drug should have been, and the misplacement of two drugs of the same drug type but of different strengths in place of each other. The results show that people might be vulnerable to confusion from drugs that have look-alike labels and also have look-alike, sound-alike drug names. In particular, when each drug label had a fairly unique colour scheme, participants were more prone to misperceive the look-alike, sound-alike drug name as the correct drug name than when no colour was used or when colour was used on the labels with no apparent one-to-one association between the label colour and the drug identity. This result could suggest a perceptual bias to perceive stimuli as the expected stimuli especially when the task involved is familiar and the stimuli look similar to the expected stimuli. Moreover, the results suggest a potential problem that may arise from standardizing existing labels if careful consideration is not given to the effects of reduced visual variations among the labels of different products on how the colours of the labels are perceived and used for drug identification. The thesis concludes with recommendations for improving the existing standard for labelling of injectable drug containers and for avoiding medication errors due to labelling and packaging in general.