Quantitative urine uric acid
This test measures the amount of uric acid in your urine.
Uric acid is a normal body waste product. It forms when chemicals called purines break down. Purines are natural substances found in the body. They are also found in many foods, such as liver, shellfish, and alcohol. They can also be formed in the body when DNA is broken down.
When purines are broken down to uric acid in the blood, the body gets rid of it when you urinate or have a bowel movement. If your body makes too much uric acid, or if your kidneys aren't working well, uric acid can build up in the blood. Uric acid levels can also increase when you eat too many high-purine foods or take medicines like diuretics, aspirin, vitamin C, and niacin. Then crystals of uric acid can form and collect in the joints. This causes painful inflammation. This condition is called gout. Too much uric acid can also lead to kidney stones.
You may need this test if your healthcare provider thinks that you have gout. Your provider may also use this test to keep track of you while you have cancer treatment or to check your urine after you have a kidney stone.
Symptoms of gout include:
Joint pain or soreness
Swelling and pain in a joint, such as the big toe, ankle, or knee
Red skin around a joint
Joints that are hot to the touch
Swelling and pain that affects only 1 joint in the body
Skin that looks shiny and is red or purple
You may also need this test if you have symptoms of kidney stones. Symptoms include:
Severe pain along your lower back. This may repeatedly get worse and then get better. The pain may also travel to your genitals.
Urgent need to urinate
Blood in your urine
Your healthcare provider may also test the pH, or acidity, of your urine and check for a substance called creatinine. You may also have a test to measure the levels of uric acid in your synovial fluid. This is the main way to diagnose gout.
Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.
Adults normally lose about 500 to 600 milligrams (mg) of uric acid in their urine every 24 hours. If you're eating a normal diet, losing more than 750 mg a day is considered too much.
If you eat lots of animal protein or purines, you may have more uric acid in your urine. A number of health problems can also cause you to make more uric acid, including:
Glycogen storage diseases
This test is done with a urine sample. Your healthcare provider may measure your uric acid levels using a 24-hour urine test. For this sample, you must collect all your urine for 24 hours. Empty your bladder completely first in the morning without collecting it. Note the time. Then collect your urine every time you go to the bathroom over the next 24 hours. You will collect it in a container that your healthcare provider or the lab gives you. Follow the directions on how to store the container.
This test poses no known risks.
Some medicines may affect your test results. They include:
Aspirin and other medicines that contain salicylate
Cyclosporine, a medicine sometimes used for autoimmune diseases
Levodopa, a medicine used to treat Parkinson disease
Some diuretic medicines, such as hydrochlorothiazide
Vitamin B-3 (niacin)
Other things that may affect your test results include:
Chemotherapy or radiation therapy to treat cancer
Foods high in purines, such as organ meats, mushrooms, some types of fish and seafood, and dried peas and beans
Ask your healthcare provider about what to do before having this test. You may need to stop eating or drinking certain foods or stop taking certain medicines beforehand. Tell your healthcare provider about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use.