Table 2.

Genotoxicity test guidelines

Test guideline	Test system	Endpoints	Remarks
Bacterial reverse mutation test OECD 471 (1997)	Strains of Salmonella Typhimurium TA1535; TA1537 or TA97a or TA97; TA98, TA100 and Escherichia coli WP2 strains or S. Typhimurium TA102	Detection of gene mutations Substitution, addition or deletion, frame‐shift and base‐pair substitutions	First screening test Easy to use Very large database of results available
In vitro mammalian cell gene mutation tests hprt or xprt genes OECD 476 (2015)	hprt: CHO, CHL and V79 lines of Chinese hamster cells, L5178Y mouse lymphoma cells and TK6 human lymphoblastoid cells xprt: CHO‐derived AS52 cells	Detection of gene mutations Including base pair substitutions, frame‐shift, small deletions and insertions	xprt (contrary to hprt) May allow the detection of large deletions and possibly mitotic recombination due to its autosomal location
In vitro mammalian cell gene mutation tests TK gene OECD 490 (2015)	L5178Y mouse lymphoma cells and TK6 human lymphoblastoid cells	Detections of gene mutations Including point mutations, frame‐shift mutations, small deletions	Preference to the mouse lymphoma assay (MLA) most commonly performed Allows also detection chromosomal events (large deletions, chromosome rearrangements and mitotic recombination)
In vitro mammalian chromosomal aberration test OECD 473 (2014)	Cell lines including Chinese hamster ovary (CHO), Chinese hamster lung V79, Chinese hamster lung ((CHL)/IU, TK6) or primary cell cultures, including human or other mammalian peripheral blood lymphocytes	Detection of chromosomes aberrations Chromatid‐ and chromosome‐type aberrations should be recorded separately and classified by subtypes (breaks, exchanges)	Resource intensive, time consuming and good expertise required Not appropriate to detect aneugens
In vitro mammalian cell micronucleus test OECD 487 (2014)	Various human or rodent cell lines or primary cell cultures	Detection of both structural and numerical chromosome aberrations Can be combined with special techniques to add mechanistic information, e.g. fluorescence in situ hybridisation (FISH)	Rapid and easy to conduct The only in vitro test that can efficiently detect both clastogens and aneugens
Transgenic rodent somatic and germ cell gene mutation assays OECD 488 (2013)	Transgenic rodents: lacZ mouse (Muta™ Mouse); gpt delta mouse and rat lacI mouse and rat (Big Blue®)	Detection of gene mutations Base pair substitutions, frameshift mutations, small insertions and deletions	Allows detection of mutations in both somatic tissues and germ lines
Mammalian erythrocyte micronucleus test OECD 474 (2014)	Rodents (usually)	Detection of both structural and numerical chromosome aberrations Can be combined with special techniques to additional mechanistic information, e.g. FISH	Detects both clastogens and aneugens Most widely used in vivo test (the only in vivo test performed when in vitro tests all negative) Proof of bone marrow exposure to be provided
Mammalian bone marrow chromosome aberration test OECD TG 475 (2014)	Rodents (usually)	Detection of structural chromosomal aberrations Not designed for detection of aneuploidy	Expertise required
In vivo Alkaline Mammalian Comet assay OECD 489 (2014)	Rodents (usually)	Detection of primary DNA damages DNA single‐ and double‐strand breaks	Allows investigating multiple tissues of animals
Unscheduled DNA synthesis (UDS) test with mammalian liver cells in vivo OECD 486 (1997)	Rat (commonly used)	Detection of DNA repair	Sensitivity has been questioned