The ratio of 5-hydroxytryptophol (5-HTOL) to 5-hydroxyindoleacetic acid (5-HIAA) in the urine can provide insight into whether a person has been drinking ethanol or if ethanol in the urine is a result of in vitro fermentation.
Serotonin is normally metabolized in the liver to a number of metabolites, most of which is 5-HIAA.
In a person who has ingested ethanol production of 5-HIAA is reduced and 5-HTOL is increased. This reversal persists for several hours after ethanol can no longer be detected in the urine.
Parameters:
(1) urinary ethanol level
(2) urinary 5-HTOL in pmol/L
(3) urinary 5-HIAA in nmol/L
ratio of urinary 5-HTOL to urinary 5-HIAA =
= (concentration of 5-HTOL in pmol/L) / (concentration of 5-HIAA in nmol/L)
Interpretation:
• The ratio of urinary 5-HTOL to 5-HIAA is normally <= 15 pmol/nmol
Urinary Ethanol |
5-HTOL to 5-HIAA |
Interpretation |
not elevated |
not elevated |
no evidence of ethanol ingestion or in vitro production |
not elevated |
elevated |
remote ethanol ingestion |
elevated |
not elevated |
in vitro ethanol production |
elevated |
elevated |
recent ethanol ingestion |
where:
• The concentrations of 5-HTOL and 5-HIAA are relatively stable over time.
• The molecular weight of 5-HIAA is 191.19
• The molecular weight of 5-HTOL is 177.2
• The quantities of these compounds is low, so accurate and reliable analytical methods are required.
Specialty: Toxicology, Emergency Medicine, Critical Care
ICD-10: ,