Serum/plasma dopamine metabolite ratio (L-OPA to HVA ratio)
This test measures the ratio of two dopamine breakdown products in your blood, which can help assess dopamine function and potential issues with its metabolism.
["This ratio helps doctors evaluate dopamine activity and may indicate conditions affecting brain chemistry or nerve function."]
Key facts at a glance
- LOINC
- 29423-1
- Short code
- PV-LU Vmax sys DOP
- Synonyms
- PV-LU Vmax sys DOP
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- us-doppler
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test looks at two dopamine metabolites—L-OPA (levodopa-derived) and HVA (homovanillic acid)—to calculate their ratio. These metabolites are byproducts of dopamine, a brain chemical involved in movement, mood, and other functions. The ratio helps identify imbalances that might suggest conditions like Parkinson’s disease, certain neurological disorders, or metabolic issues.
Why It’s Done
Your doctor may order this test if you have symptoms like movement problems, mood changes, or other signs of dopamine-related disorders. It’s sometimes used in research or specialized care for conditions affecting dopamine pathways.
Sample Collection
A blood sample is drawn from a vein, usually in your arm. The blood is separated into serum or plasma for testing. This is a standard blood draw procedure, and you may feel a slight pinch when the needle is inserted.
What to Expect Before the Test
No special preparation is needed, but you may want to avoid caffeine or certain medications that could affect dopamine levels for a few days before testing. Let your doctor know about any medications you’re taking.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is primarily used in research or specialized clinical settings to evaluate dopamine metabolism. Abnormal ratios may suggest conditions like Parkinson’s disease, dopamine transporter disorders, or metabolic imbalances. It’s not a routine screening test but may be part of a broader evaluation for neurological or psychiatric concerns.
Short name
Dopamine metabolite ratio
Frequently asked questions
When might this test be recommended?
What does a high or low ratio mean?
Can this test be done at home?
Sources
- 1
- 2Lab Tests OnlineSource
- 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