Hvis det vides, at dyr af denne stamme og herkomst giver problemer med at opfylde de accepterede kriterier for overlevelse i langvarige forsøg [se Guidance Document No. 116 (7)], bør det overvejes at bruge en stamme, der har en acceptabel overlevelsesfrekvens, til det langvarige forsøg.
The carcinogenicity study should preferably be carried out in animals from the same strain and source as those used in preliminary toxicity study(ies) of shorter duration although, if animals from this strain and source are known to present problems in achieving the normally accepted criteria of survival for long-term studies [see Guidance Document No 116 (7)], consideration should be given to using a strain of animal that has an acceptable survival rate for the long-term study.