What is the test system in GLP?

In GLP (Good Laboratory Practice), the test system refers to the biological, chemical, or physical model used to assess the effects of a test item during a study. It is the core element that interacts directly with the product being tested — for example, laboratory animals, cell cultures, microorganisms, or in vitro systems. The GLP test system must be carefully selected, characterized, and maintained to ensure that study results are accurate, reproducible, and scientifically valid.

A GLP-compliant test system must follow specific conditions such as controlled temperature, humidity, and light cycles for animals, or validated culture conditions for cells. Documentation of all variables — including feed, housing, and equipment — is mandatory. The study director and Quality Assurance team verify that the test system remains consistent throughout the experiment. In short, the test system is the foundation of every GLP study, ensuring data integrity and reliability for toxicology, pharmacology, or safety testing.