Urinary neurotransmitter testing: considerations of spot baseline norepinephrine and epinephrine

BACKGROUND: The purpose of this paper is to present the results of statistical analysis of spot baseline urinary norepinephrine and epinephrine assays in correlation with spot baseline urinary serotonin and dopamine findings previously published by the authors. Our research indicates a need for physicians and decision-makers to understand the lack of validity of this type of spot baseline monoamine testing when using it in the decision-making process for neurotransmitter deficiency disorders. METHODS: Matched-pairs t-tests were performed for a group of subjects for whom spot baseline urinary norepinephrine and epinephrine assays were performed on samples collected on different days then paired by subject. RESULTS: The reported laboratory test results for urinary serotonin, dopamine, norepinephrine, and epinephrine, obtained on different days from the same subjects, differed significantly and were not reproducible. CONCLUSION: Spot baseline monoamine assays, in subjects not suffering from a monoamine-secreting tumor, such as pheochromocytoma or carcinoid syndrome, are of no value in decision-making due to this day-to-day variability and lack of reproducibility. While there have been attempts to integrate spot baseline urinary monoamine assays into treatment of peripheral or central neurotransmitter-associated disease states, diagnosis of neurotransmitter imbalances, and biomarker applications, significant differences in day-to-day reproducibility make this impossible given the known science as it exists today.