plasma N-desmethylclozapine measurement (EFO_0600039, an Experimental Factor Ontology identifier) is quantification of the levels of N-desmethylclozapine, also known as norclozapine, in blood plasma. N-desmethylclozapine is a major active metabolite of clozapine, an antipsychotic drug used to treat schizophrenia. Also known as: plasma norclozapine measurement.