Lab test5 min read
Uric acid test
A blood or urine test that measures uric acid, a waste product made when the body breaks down purines. It helps diagnose gout and monitor the risk of kidney stones.
The body makes uric acid when it breaks down purines from dying cells and some foods and drinks; the blood carries it to the kidneys, which pass it out in urine. If the body makes too much or the kidneys remove too little, it builds up and forms crystals in and around joints, causing gout, and it can contribute to kidney stones.
The blood test is usually done with a joint fluid test to diagnose gout, and to monitor people having chemotherapy, which releases purines. A 24-hour urine test shows whether high uric acid is causing kidney stones. High blood levels can be linked to diet (red and organ meats, some seafood, alcohol and high-fructose corn syrup) and to gout, kidney disease and stones, and some cancers. Many people have high levels without any health problems.
What is it?
According to MedlinePlus, this test measures uric acid in a blood or urine sample. The body makes uric acid when it breaks down purines, substances found in dying cells and in some foods and drinks.
The blood carries uric acid to the kidneys, which filter it out in urine. If the body makes too much or the kidneys remove too little, it builds up and forms crystals in and around joints, causing gout, and it can contribute to kidney stones or kidney failure — though not everyone with high levels has these problems.
Why is it done?
Blood test: to help diagnose gout, usually with a joint fluid test, and to monitor people having chemotherapy or some other cancer treatments. NIAMS notes that doctors may order a blood urate test when diagnosing gout.
Urine test: to see whether high uric acid is causing kidney stones, and to monitor stone risk in people with gout.
Symptoms that may lead to the test include those of gout, which usually affects one joint at a time, most often the big toe (intense pain, swelling, redness, warmth and limited movement), and signs of a kidney stone such as pain in the lower belly, side, groin or back and blood in the urine.
Preparation
Many medicines, including aspirin, and niacin (vitamin B3) can affect the result. Tell your doctor about all your medicines, but don't stop any without talking to them first.
How is it done?
Blood: a health professional takes a sample from a vein in your arm with a small needle, usually in less than five minutes.
24-hour urine: pass urine as usual the first time, discard it and note the time; then collect all your urine for the next 24 hours in the container, keeping it in the fridge or on ice, pass urine into it one last time at the end, and return it as instructed.
Understanding the result
High blood levels can happen if the body makes too much or the kidneys don't clear it well, and diet can contribute — including red and organ meats, some seafood, alcohol and high-fructose corn syrup. Possible causes include gout, kidney disease or stones, some blood cancers, side effects of cancer treatment, alcohol use disorder and pre-eclampsia.
Low blood levels are uncommon and usually cause no problems.
In urine, high levels may be linked to gout, kidney stones, some cancers and obesity, and low levels to kidney disease, lead poisoning or alcohol use disorder.
The source gives no numeric ranges: rely on the reference range in your laboratory report and on your doctor's interpretation.
Risks and side effects
MedlinePlus lists no known risks for the blood or urine test; you may have slight pain or bruising where the needle went in.
Limits of the test
A high result doesn't always mean a condition that needs treatment: many people have high levels without health problems. To diagnose gout, NIAMS also lists testing joint fluid for urate crystals, and ultrasound or a special CT scan.
After the test
Medicines or changes in diet may help lower it; your doctor explains your result and decides whether treatment is needed.
Common questions
Do I need to fast before a uric acid test?
MedlinePlus doesn't mention fasting for this test, but some medicines such as aspirin and niacin affect it; tell your doctor about your medicines and follow the laboratory's instructions.1
Does high uric acid mean I have gout?
Not necessarily: many people have high levels without symptoms, and the diagnosis also relies on symptoms and a joint fluid test.12
Which foods raise it?
MedlinePlus lists red and organ meats, some seafood, alcohol and high-fructose corn syrup.1
Questions for your doctor
- Do I need a blood test or a 24-hour urine test?
- Do my medicines affect the result?
- Does a high level need treatment if I have no symptoms?
- What should I change in my diet?
References
- 1MedlinePlus / NLM. Uric Acid Test. medlineplus.gov/lab-tests/uric-acid-test/Health agencies & guidelines · Accessed 2026-10-11
- 2NIAMS / NIH. Gout — Diagnosis, Treatment, and Steps to Take. www.niams.nih.gov/health-topics/gout/diagnosis-treatment-and-steps-to-takeHealth agencies & guidelines · Accessed 2026-10-11
Review status: Edited content · Last updated:
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Educational content only — no diagnosis, and no substitute for a clinician.