A PhD student used a DNA sample for her experiments that she received from a colleague. Since she trusted it, she didn’t verify the identity of the sample.

She worked on the sample for several months, but couldn’t get meaningful results. Finally, the DNA sample was sequenced to see whether there was something wrong with the sample. It turned out that the sample was mixed up due to a mistake in labelling. Months of hard work had been completely in vain.

The example shows that correct and clear labelling is important in the handling of physical samples. If there is uncertainty regarding the identity of a sample, it should be checked before it is further used in experiments. In addition, samples and the corresponding information should be documented in a physical and/or digital inventory.