Understanding Your Laboratory Test: What It Is, How It Is Done, and Why You May Need It
This test checks for the presence of 4-hydroxyphenylpyruvate, a substance that may appear in urine when the body has trouble breaking down the amino acid tyrosine.
{"A simple urine test to detect a metabolic byproduct","Helps diagnose disorders of tyrosine metabolism","Abnormal results may indicate genetic conditions or liver problems","Sample collected as a routine urine specimen","Follow-up testing may be needed if results are abnormal"}
Key facts at a glance
- LOINC
- 29871-1
- Short code
- 4HPYU
- Synonyms
- 4OH-phenylpyruvate Ur Ql
- Category
- chemistry
- Sample
- urine
- Container
- Clean, sterile, labeled urine container (plastic or glass)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
- CPT
- 82131
- SNOMED
- 314275004
- Specimen volume
- Minimum 5 mL, preferred 10 mL
- Stability
- Refrigerated (2-8°C) for up to 7 days; frozen (-20°C or below) for up to 30 days
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 72–168 hours
- Order
- routine
This test is a diagnostic procedure that helps your healthcare provider evaluate your health by measuring specific substances or functions in your body. The results provide important information that guides diagnosis, treatment decisions, and ongoing monitoring of your condition.
The 4-Hydroxyphenylpyruvate test is a urine test that looks for the presence of 4-hydroxyphenylpyruvate, which is a normal intermediate product when your body breaks down the amino acid tyrosine. Normally, this substance is further broken down and not found in significant amounts in urine. When the body cannot properly process tyrosine due to enzyme deficiencies or liver problems, 4-hydroxyphenylpyruvate can accumulate and be detected in urine.
The test is usually performed in a clinic, hospital, or laboratory by a trained member of your care team. A small sample, such as blood, urine, or tissue, may be collected, or a noninvasive measurement may be taken, and the sample or reading is then analyzed and interpreted.
A urine sample is collected in a sterile container. This can be a random urine sample collected at any time of day, or in some cases, a timed collection may be requested. The sample is then sent to a laboratory where it is analyzed using special chemical methods to detect whether 4-hydroxyphenylpyruvate is present. No fasting or special preparation is typically required for this test.
Your doctor may order this test to help diagnose a medical condition, investigate symptoms you are experiencing, screen for disease before symptoms appear, or check how well a current treatment is working. It can also be used to track changes in your health over time.
Your healthcare provider may order this test if you have symptoms suggesting a metabolic disorder, such as developmental delays, liver problems, or unusual body odor. It is also used as part of newborn screening follow-up or when hereditary tyrosinemia is suspected. The test helps doctors determine if there is a problem with how your body processes the amino acid tyrosine.
Reference range
Not detected or below limit of quantificationN/A
No special preparation required. Collect random urine sample in clean, sterile container. Avoid contamination with toilet paper or feces. Inform laboratory of any medications or supplements being taken.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The presence of 4-hydroxyphenylpyruvate in urine is considered abnormal and may indicate: Tyrosinemia type II or III (genetic disorders affecting tyrosine metabolism), liver disease or liver dysfunction that affects metabolism, deficiency of the enzyme 4-hydroxyphenylpyruvate dioxygenase (HPPD), or other metabolic disorders. Positive results typically require follow-up testing, including blood tests and possibly genetic testing, to confirm the specific condition. Early diagnosis is important as some causes are treatable with dietary modifications or medication.
Frequently asked questions
Does a positive result mean I have a serious disease?
Do I need to fast before this test?
Is the test painful?
How long does it take to get results?
Can medications affect the 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