VALIDATION - LESSONS LEARNED FROM PRACTICAL EXPERIENCE

With regard to the problems encountered and the experience gained in v alidation studies conducted in the past, suggestions have been made co ncerning criteria for the selection of the tests and laboratories to b e included in a validation study, the selection and distribution of te st chemicals, and procedures for the handling, analysis and interpreta tion of the resulting data. In particular, tests should have been deve loped to the extent that detailed protocols and standard operating pro cedures have been produced and evaluated. The laboratories should be c hosen on the basis of evidence of their appropriate experience, compet ence and ability to comply with good laboratory practice (GLP) require ments. The choice of test chemicals depends primarily on the goals of the validation study and on the availability of reliable in vivo toxic ity data of high quality. A biostatistician should be involved in the initial design of the validation study as well as in the analysis of t he resulting data. The quality of the in vivo and in vitro data must b e ensured, prior to determining the reproducibility and predictivity o f the alternative test.