Inactivation of isoniazid by Canadian Eskimos and Indians.

Phenotyping for isoniazid inactivation in Canadian Eskimos and Indians showed that the former are all fast acetylators, while only 63.4% of the Indians examined belonged to the same group. Further studies are suggested to confirm this initial finding.During the investigation metabolic studies were carried out to devise a reliable urine test for phenotyping of isoniazid inactivators, to replace the fall-off technique which required venipunctures. The simplicity of the new urine test makes it suitable for mass examinations.