Overview

The chromosome aberration test (CAT) is designed to evaluate the potential of a test compound to induce structural chromosomal abnormalities such as breaks and exchanges.

Screening and Regulatory Support

  • The CAT can be performed in primary human peripheral blood lymphocytes (HPBL) or established cell lines, such as Chinese hamster ovary (CHO) cells.
  • Cultures are incubated with several concentrations of the test compound for 3 to 4 hours in the presence and absence of metabolic activation (S9) and for 21 hours in the absence of S9.
  • A positive outcome is characterized by a statistically significant, dose-dependent increase in aberrant cells that exceeds historical negative control limits.
Metaphase spread of human lymphocyte showing multiple chromosome aberration

Metaphase spread of human lymphocyte showing multiple chromosome aberration

When to Perform

  • Screening
  • IND-enabling studies
    • As part of the ICH S2(R1) standard battery
  • REACH requirement
    • As part of Annex VIII testing