Understanding Your Medical Test: What It Is, Why It Is Done, and What the Results Mean for Your Health
A urine test that detects the presence of 4-Hydroxyphenylacetate, a substance that can indicate certain metabolic disorders or exposure to specific chemicals.
{"This test measures 4-Hydroxyphenylacetate in your urine","Abnormal results may suggest metabolic disorders or chemical exposure","The test requires a simple urine sample","Results help doctors diagnose conditions affecting tyrosine metabolism","Follow your doctor's instructions for sample collection"}
Key facts at a glance
- LOINC
- 27270-8
- Short code
- 4-HPA U
- Synonyms
- 4OH-phenylacetate Ur Ql
- Category
- chemistry
- Sample
- urine
- Container
- Sterile, labeled urine container (primary); transfer tube for aliquoting
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) or Gas Chromatography-Mass Spectrometry (GC-MS)
- CPT
- 82131
- SNOMED
- 30856009
- Specimen volume
- Minimum 5 mL, preferably 10-15 mL of well-mixed urine
- Stability
- Room temperature: 24-48 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 24–72 hours
- Order
- routine
What is this test, what does it actually measure in my body, and how will my doctor use the results to guide my care?
The 4-Hydroxyphenylacetate urine test is a laboratory analysis that checks whether 4-Hydroxyphenylacetate is present in your urine. 4-Hydroxyphenylacetate is a natural compound (metabolite) produced when your body breaks down certain amino acids, particularly tyrosine. Under normal circumstances, small amounts may be present in urine, but elevated levels can indicate health problems.
Why might I need this test, and what symptoms, risk factors, or health conditions could lead my doctor to order it?
Your doctor may order this test if they suspect a metabolic disorder, particularly conditions affecting how your body processes tyrosine and phenylalanine. It may also be used to monitor certain genetic conditions or to check for exposure to specific environmental chemicals that affect tyrosine metabolism. Symptoms that might prompt testing include unusual body odor, developmental delays in children, or neurological symptoms.
How is this test performed, how should I prepare for it beforehand, and what can I expect during the procedure itself?
The test requires a clean-catch urine sample. You will be given instructions on how to collect a mid-stream urine sample to avoid contamination. The sample is then sent to a laboratory where it is analyzed using specialized equipment to detect and measure 4-Hydroxyphenylacetate levels. No special preparation is typically needed, but follow any specific instructions from your healthcare provider.
What do the results of this test mean, and how will my doctor explain normal and abnormal values along with any follow-up steps?
Results are typically reported as either 'Present' or 'Not Detected,' or as a concentration value. The presence of 4-Hydroxyphenylacetate in urine at elevated levels may indicate: tyrosinemia (a group of metabolic disorders), certain liver diseases, or exposure to specific substances. Your doctor will interpret your results in the context of your symptoms, medical history, and other test results.
Reference range
Not Detected - Negative for 4-HydroxyphenylacetateN/A
No specific fasting required. Avoid taking vitamin supplements or medications that may interfere with the test for 24-48 hours before sample collection. Inform the laboratory of any current medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
Is this test painful?
How long does it take to get results?
Do I need to fast before this test?
What happens if my results are abnormal?
Can medications affect my test results?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy