Overview

The comet assay, also known as the single-cell gel electrophoresis (SCGE) assay, measures DNA strand breaks in individual cells.

Additional Support and Regulatory Follow-Up

When standard genetic toxicology assays return positive results, additional assays may be required to determine mechanism of action and qualify human risk.

  • The comet assay, also known as the single-cell gel electrophoresis (SCGE) assay, measures DNA strand breaks in individual cells.
  • Appropriate tissues are collected and processed to a single-cell suspension layered over a slide in a thin film of agarose.
  • Electrophoresis is then performed to identify DNA damage by the migration of small fragments of broken DNA away from the nucleus forming a “tail” to the dense circular comet head of undamaged DNA.
  • Testing is available for blood, liver, kidney, lung, bronchoalveolar lavage cells, stomach, duodenum, intestine, bone marrow, nose and eye.
    • New tissues can be validated upon request.

When to Perform

  • IND-enabling studies
    • As part of the ICH S2(R1) standard battery (Option 2)
    • As a follow-up to a positive in vitro mammalian cell clastogenic response
  • REACH requirements
    • As a follow-up to a positive result in an Annex VII or VIII genotoxicity test
Comet quantification on liver cell of rat treated with ethyl methanesulfonate

Comet quantification on liver cell of rat treated with ethyl methanesulfonate