microdetermination

noun
mi·​cro·​de·​ter·​mi·​na·​tion | \ -di-ˌtər-mə-ˈnā-shən How to pronounce microdetermination (audio) \

Medical Definition of microdetermination

: a quantitative chemical analysis in which the amount of a substance presumed to be present in a sample in very small quantities is ascertained

called also microestimation