Uric acid

What is a uric acid test?

This test measures the amount of uric acid in a sample of your blood or urine (pee). Uric acid is a normal waste product that your body makes when it breaks down chemicals called purines. Purines come from your cells when they die. Purines are also found in many foods and beverages.

Most uric acid dissolves in your blood. Your kidneys filter the uric acid out of your blood, and it leaves your body in your urine. If uric acid builds up in your blood, it can form needle-shaped crystals in and around your joints. This condition is called gout.

Gout is a type of arthritis that causes painful swelling in your joints. High uric acid levels can also cause kidney stones, or kidney failure. But not everyone with high levels of uric acid will have these problems.

Other names: serum urate, UA, uric acid: serum and urine

What is it used for?

A uric acid blood test may be used to:

  • Help diagnose gout, usually when done with a synovial fluid analysis.
  • Monitor uric acid levels in people who are having cancer chemotherapy or certain other cancer treatments. When treatment kills cancer cells quickly, they release large amounts of purines into the blood. This can lead to serious problems from high uric acid levels. Testing helps catch an increase in uric acid so it can be treated early.

A uric acid urine test may be used to:

  • Help find out whether high levels of uric acid are causing kidney stones
  • Monitor the risk of developing kidney stones in people who have gout

Why do I need a uric acid test?

You may need a uric acid blood test if you:

  • Have symptoms of gout. Symptoms usually happen in one joint at a time. The big toe is most commonly affected, but your other toes, ankle, or knee may have symptoms, which include:
    • Intense pain
    • Swelling
    • Redness
    • Feeling warm
  • Had or are having certain types of cancer treatments.

You may also need a uric acid urine test if you:

  • Have symptoms of a kidney stone, including:
    • Sharp pain in your lower abdomen (belly), side, groin or back
    • Blood in your urine
    • Frequent urge to urinate (pee)
    • Not being able to urinate at all or only urinating a little bit
    • Pain when urinating
    • Cloudy or bad-smelling urine
    • Nausea and vomiting
    • Fever and chills
  • Have gout and your health care provider wants to monitor your risk for developing kidney stones

What happens during a uric acid test?

A uric acid test may be done as a blood test or a urine test. Your provider will decide which test you need.

For a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

For a uric acid urine test, you’ll need to collect all your urine during a 24-hour period. This is called a 24-hour urine sample test. You will be given a special container to collect your urine and instructions on how to collect and store your samples. Your provider will tell you what time to start. The test generally includes the following steps:

  • To begin, urinate in the toilet as usual. Do not collect this urine. Write down the time you urinated.
  • For the next 24 hours, collect all your urine in the container.
  • During the collection period, store the urine container in a refrigerator or in a cooler with ice.
  • 24 hours after starting the test, try to urinate if you can. This is the last urine collection for the test.
  • Return the container with your urine to your provider’s office or the laboratory as instructed.

Will I need to do anything to prepare for the test?

Usually, you don’t need any special preparations for a uric acid blood test. Many medicines, including aspirin, can affect your uric acid levels. Taking niacin (vitamin B-3) can also affect your results. So, be sure to tell your provider about all the medicines you take. But don’t stop taking any medicines without talking with your provider first.

Are there any risks to the test?

There is no known risk to having a uric acid blood or urine test.

What do the results mean?

High uric acid levels in a blood test may happen if:

  • Your body makes too much uric acid
  • Your kidneys can’t remove uric acid from your blood
  • You are eating too many foods that cause high levels of purines such as:
    • Red meat and organ meats, including liver and kidney
    • Certain kinds of seafood, including shellfish, anchovies, sardines, trout, and tuna
    • Alcohol (all types)
    • High fructose corn syrup in soda and sweets

Your provider may order more tests to help diagnose what’s causing the problem. High levels of uric acid may be related to many conditions, including:

  • Gout
  • Kidney disease
  • Leukemia, multiple myeloma, or cancer that has spread in your body (metastatic cancer)
  • Side effects from certain cancer treatments
  • Alcohol use disorder
  • Preeclampsia, a condition that can cause dangerously high blood pressure in pregnant women

Low levels of uric acid in blood are uncommon and usually don’t cause health problems. Health conditions that are related to low uric acid levels are usually diagnosed using other tests.

High uric levels in urine, may be related to:

  • Gout
  • Kidney stones or having a high risk for kidney stones
  • Leukemia, multiple myeloma, or cancer that has spread in your body
  • Obesity
  • An inherited genetic condition, such as Lesch-Nyhan syndrome, that makes it hard for your body to get rid of uric acid

Low levels of uric acid in urine may be related to kidney disease, lead poisoning, or alcohol use disorder.

If your results show a high level of uric acid in your blood or urine, it doesn’t always mean you have a condition that needs treatment. Many people have high levels of uric acid without having health problems.