Definition (general):

Human biological monitoring is a procedure to determine if and to what extent chemical substances from the environment are absorbed in the body.


Definition (more precise):

Human biological monitoring is the is the standardized and repeated systematic collection, pretreatment, storage, and analysis of body tissues to assess the internal dose of a xenobiotic substance by analysis of the parent substance or a product of biotransformation.


For more background on human biological monitoring please refer to: