Toluene as Hippuric Acid, Occupational Exposure, Urine
Use
This test is used to measure the level of hippuric acid in urine, which is a primary metabolite of toluene. Toluene is a common industrial solvent that, when inhaled, poses risks to human health. The test is primarily employed for occupational health monitoring to assess the exposure levels of individuals working in environments with potential toluene exposure. Measuring hippuric acid in urine helps evaluate this exposure level, allowing for timely management and reduction of health risks related to overexposure.
Special Instructions
The test requires a 10 mL aliquot of random or spot urine collected at the end of a work shift. It is critical that specimens are kept refrigerated during transport to prevent the loss of volatile compounds. Tubes should be filled to minimize headspace, which can lead to the loss of analytes.
Limitations
The test measures hippuric acid as a marker of toluene exposure but does not directly measure toluene levels. Hippuric acid levels can also be influenced by dietary sources such as benzoic acid, commonly found in various fruits and food products, which may affect test accuracy. Thus, it is important to consider dietary intake and timing of exposure when interpreting results. The test cannot determine historical exposure beyond recent contact, as hippuric acid quickly metabolizes and is excreted. The Biological Exposure Index (BEI) for hippuric acid represents concentrations expected at the end of a work shift assuming adherence to the ACGIH-recommended TLVs for toluene.
New York Approved
Methodology
Mass Spectrometry (GC-MS)
Biomarkers
LOINC Codes
- 2161-8
- 6709-0
- 13754-7
Result Turnaround Time
7-8 days
Related Documents
For more information, please review the documents below
Specimen
Urine
Volume
10 mL
Minimum Volume
1.2 mL
Collection Instructions
Collect a random or spot urine at the end of shift. Transport refrigerated and ensure tubes are filled to prevent loss of volatile compound.
Storage Instructions
Refrigerated (preferred) for up to 14 days; can be frozen for 180 days.
Causes for Rejection
Hemolysis, Lipemia, Icterus, Other conditions not specified.
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 14 days |
| Frozen | 180 days |