The main issue is that the comet assay does not directly measure the number of specific DNA lesions, but rather measures the migration of DNA in agarose gels as a result of the relaxation produced by strand breaks under alkaline conditions. A recent review summarized the plenitude of procedure descriptions and technical recommendations for comet assays that have been published in the past 20 years, and highlighted the problem of inter-laboratory variation in DNA damage levels 15. This variation could hamper inter-laboratory data comparison and interpretation, as well as attempts to standardize methods and promote the use of reference standards 5, 6, 7, 8, 9, 10, 11, 12, 13, 14. However, international ring trials have identified substantial variations in comet assay procedures and primary descriptors (such as %DNA in tail) between laboratories. The alkaline comet assay is a technically simple, sensitive assay to detect DNA damage (strand breaks and other lesions that are converted into strand breaks under alkaline conditions) and DNA repair activity 1, 2, 3, 4. Adherence to MIRCA recommendations should ensure that comet assay results can be easily interpreted and independently verified by other researchers.

These recommendations differentiate between ‘desirable’ and ‘essential’ information: ‘essential’ information refers to the precise details that are necessary to assess the quality of the experimental work, whereas ‘desirable’ information relates to technical issues that might be encountered when repeating the experiments. Here, we present a Consensus Statement for the Minimum Information for Reporting Comet Assay (MIRCA) providing recommendations for describing comet assay conditions and results. These differences may be attributed to protocol differences, although it is difficult to identify the relevant conditions because detailed comet assay procedures are not always published. However, there are interlaboratory differences in reported levels of baseline and induced damage in the same experimental systems.

The comet assay is a widely used test for the detection of DNA damage and repair activity. Nature Protocols volume 15, pages 3817–3826 ( 2020) Cite this article

Minimum Information for Reporting on the Comet Assay (MIRCA): recommendations for describing comet assay procedures and results

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