Serotonin metabolism can be affected by alcohol consumption, resulting in increased 5-hydroxytryptophol (5-HTOL) and decreased 5-hydroxyindole-3-acetic acid (5-HIAA). This change can be detected for several hours after alcohol consumption.


ratio of urinary 5-HTOL to 5-HIAA =

= (urinary 5-HTOL in pmol) / (urinary 5-HIAA in nmol)


ratio of urinary 5-HTOL to creatinine =

= (urinary 5-HTOL in pmol) / (urinary creatinine in mmol)



• upper reference level for 5-HTOL to 5-HIAA ratio: 20 pmol/nmol

• upper reference level for 5-HTOL to creatinine ratio: 30 pmol/mmol

• An increase in 5-HTOL indicates recent alcohol drinking (within past 24 hours).

• Measurement of the 5-HTOL to 5-HIAA ratio preferred to 5-HTOL to creatinine ratio, since creatinine excretion is affected by muscle activity or muscle disorders.

• Daily monitoring of 5-HTOL and 5-HTOL to 5-HIAA ratio can help to detect relapse in alcoholics


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