Which tests measure Serotonin (5-Hydroxytryptamine), 24-Hour Urine?

Serotonin (5-Hydroxytryptamine), 24-Hour Urine is measured in 1 test on BiomarkersLabs.com, including NeuroBasic Profile — 24 Hour Urine.

Biomarker Reference · 5-HT

What does the Serotonin (5-Hydroxytryptamine), 24-Hour Urine test measure?

Q: What is the reference range for Serotonin (5-Hydroxytryptamine), 24-Hour Urine?

The standard reference range for Serotonin (5-Hydroxytryptamine), 24-Hour Urine is 46–272 µg/24h # REVIEWER FLAG: Confirm Doctor's Data reference range — values vary between laboratory platforms and are age- and sex-adjusted in some protocols.. Reference ranges vary by laboratory and assay platform — interpret in context of the issuing laboratory's stated range.

Serotonin (5-Hydroxytryptamine), 24-Hour Urine (5-HT) is a clinical biomarker used in neurological-mental-health assessment. Serotonin is synthesised from dietary tryptophan via hydroxylation to 5-hydroxytryptophan (5-HTP) and subsequent decarboxylation. It is measured in 1 laboratory test on BiomarkersLabs.com.

Reference Range: 46–272 µg/24h # REVIEWER FLAG: Confirm Doctor's Data reference range — values vary between laboratory platforms and are age- and sex-adjusted in some protocols.
Units: µg/24h, nmol/24h
Measured In: 1 test
Category: Neurological

Functional medicine optimalFunctional medicine practitioners typically target mid-to-upper reference range; optimal thresholds are not standardised. # REVIEWER FLAG: Confirm whether Doctor's Data documentation cites an optimal or functional range distinct from the reference range.

What is Serotonin (5-Hydroxytryptamine), 24-Hour Urine?

Serotonin is synthesised from dietary tryptophan via hydroxylation to 5-hydroxytryptophan (5-HTP) and subsequent decarboxylation. Approximately 90–95% of the body's total serotonin is produced in enterochromaffin cells of the gastrointestinal mucosa, with the remaining 5–10% synthesised in the raphe nuclei of the brainstem. Urinary serotonin therefore predominantly reflects peripheral and enteric production rather than central serotonergic neurotransmission. It is catabolised by monoamine oxidase (MAO) to 5-hydroxyindoleacetic acid (5-HIAA), which is the principal urinary metabolite.

Why is Serotonin (5-Hydroxytryptamine), 24-Hour Urine measured?

Urinary serotonin measurement in the functional medicine context is used to assess serotonin synthesis capacity as a surrogate for tryptophan availability and cofactor sufficiency (pyridoxal-5-phosphate, iron, zinc). Reduced levels may reflect precursor depletion, malabsorption, or impaired enteric synthesis and are used to guide amino acid supplementation with L-tryptophan or 5-HTP. Practitioners should note that urinary levels do not directly reflect CNS serotonin activity — interpretation as a proxy for brain serotonergic tone requires clinical correlation and is not validated by mainstream psychiatry.

Reference ranges

Standard reference: 46–272 µg/24h # REVIEWER FLAG: Confirm Doctor's Data reference range — values vary between laboratory platforms and are age- and sex-adjusted in some protocols.
Functional medicine optimal: Functional medicine practitioners typically target mid-to-upper reference range; optimal thresholds are not standardised. # REVIEWER FLAG: Confirm whether Doctor's Data documentation cites an optimal or functional range distinct from the reference range.
Units: µg/24h, nmol/24h

Reference ranges vary by laboratory and assay platform. Interpret in context of the issuing laboratory's stated range.

Tests that measure Serotonin (5-Hydroxytryptamine), 24-Hour Urine

1 test on BiomarkersLabs.com include this biomarker.

BML-NMH-001Comprehensive

NeuroBasic Profile — 24 Hour Urine

Serotonin (5-Hydroxytryptamine), 24-Hour Urine reference range in this test: 46–272 µg/24h # REVIEWER FLAG: Confirm Doctor's Data reference range — values vary between laboratory platforms and are age- and sex-adjusted in some protocols.

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