Test Overview

The effieicency of major pathways of liver detoxification can be evaluated by testing saliva and urine samples after provocation with measured doses of common over-the-counter medications (caffeine, asprin, acetaminophen). Not recommended for children under 12 years old.

Test Indications

Sample Collection

  1. Avoid taking any medications containing asprin or acetaminophen (Tylenol) for 24 hours prior to starting the test and during the test.
  2. Avoid any foods containing caffeine (NoDoze, energy drinks, colas, tea, coffee, chocolate) for 24 hours prior to starting the test and during the test.
  3. Avoid alcohol, fruit, licorice, peppermint, nuts and seeds for 24 hours prior to starting the test and during the test.
  4. Do not collect urine sample during menstruation.

Your doctor or lab may have different instructions that supersede the above.


82492Acetaminophen Metabolites 
80101Caffeine Clearance 
84311o-Hydroxyhippuric Acid 

Labs Performing Test

Name of LabLab CodeEstimated CostProcessing TimeComments
Metametrix 0180$197  

Costs cited are subject to change and may be reduced by insurance or cash discounts and increased by sample collection fees.


Caffeine Clearance

o-Hydroxyhippuric Acid

Acetaminophen Sulfate

Acetaminophen Glucuronide

Urine Lipid Peroxides

Ratio Phase I/Phase II


Unless specifically noted above, references used in the construction of this web page include the following:

[FDM] Lecture notes from Functional Medicine University.

[SCNM] Lecture notes from Southwest College of Naturopathic Medicine.

[UT] Lecture notes from the University of Tennessee graduate programs in Chemistry and Biochemistry.

[MM] Metametrix Clinical Laboratory.