Therapeutic Drug Monitoring (TDM) is based on the assumption that there is a relationship between the blood concentration and clinical effect (therapeutic improvement and adverse effects). It also assumes there is a concentration range of the drug which is characterized by maximal effectiveness and maximal safety, the “therapeutic window”.

The Diagnotix kit for measuring antipsychotics includes aripiprazole, olanzapine, risperidone (including the metabolite 9-OH-risperidone, also paliperidone), quetiapine, haloperidol, and clozapine.
The antipsychotics are used for the treatment of schizophrenia and schizoaffective disorder, moderate to severe manic episodes, bipolar disorder, treatment of persistent aggression and psychotic symptoms in patients with moderate to severe Alzheimer's dementia, psychosis during the course of Parkinson's disease, acute treatment of delirium, treatment of tic disorders including Tourette's syndrome, and treatment of mild to moderate chorea in Huntington's disease