Used as a biomarker in clinical diagnostics, particularly in the assessment of neuroblastoma and other catecholamine-secreting tumors. Measured in urine and plasma, elevated levels help in monitoring disease progression and response to treatment. Also studied in neuroscience research for its role in dopamine metabolism, providing insights into neurological disorders such as Parkinson’s disease and schizophrenia. Its presence in biological fluids reflects central dopaminergic activity, making it valuable in psychopharmacology for evaluating the effects of antipsychotic and dopaminergic drugs.