Uric acid is a chemical that is produced when the body breaks down certain foods that contain purines, such as:
- dried beans
- beer and wine
Purines are also created through the natural process of cell breakdown in the body.
Most uric acid is dissolved in the blood, transported to the kidneys, and then expelled from your body through urine. However, sometimes the body produces too much uric acid or the kidneys aren’t working well enough to expel enough of the uric acid through your urine.
Hyperuricemia is the disorder that occurs when you have too much uric acid in the body. Increased cell death, because of cancer or cancer treatments, can also lead to an accumulation of uric acid in the body. It is also possible to have too little uric acid in the body, called hypouricemia.
The uric acid test determines how much uric acid is in the urine. The test can help determine how well the body produces and removes uric acid.
Most commonly, your doctor will recommend a uric acid test when they suspect you have increased levels of uric acid in your body.
The test may be used to:
The uric acid urine test is performed using a urine sample. It may seem awkward or uncomfortable to have to urinate into a cup, but no physical discomfort should occur.
Your doctor will discuss your current medications to ensure you are not taking anything that could affect the results. Alcohol, certain medications (such as aspirin and ibuprofen), high levels of vitamin C, and dyes used in X-rays may lead to abnormal results. Be sure to tell your doctor what prescription, over-the-counter medications, or supplements you are taking.
To test the level of uric acid in the urine, your doctor will need to collect a 24-hour urine sample. Your doctor will describe the collection procedure, but generally you will eat and drink normally, although you should refrain from drinking alcohol immediately before and during the collection time. Usually you will be asked not to eat or drink for four hours before the test.
As the name suggests, you will need to collect a sample of all urine leaving the body over a 24-hour period. However, you will not collect the urine first thing in the morning. Note that time, and then collect all urine for the remaining 24 hours.
Be sure to wash your hands carefully before and after collecting each sample. Be sure to cap the containers tightly, label, and return the samples to the doctor as instructed. Samples may need to be refrigerated.
Once collected, the urine is sent to the laboratory for analysis.
A normal uric acid level in the urine is 250 to 750 milligrams over 24 hours.
High levels of uric acid in the urine may suggest:
- a diet high in foods containing purines
- multiple myeloma
- metastatic cancer (spreading)
- bone marrow disorders (such as leukemia)
- kidney disorders
- liver disease
- Lesch-Nyhan syndrome (an inherited condition)
Low levels of uric acid in the urine may suggest:
- lead poisoning
- liver or kidney disease
- a diet low in purines
For the most part, testing for uric acid is performed to help diagnose kidney stones or to monitor gout. If your doctor suspects any of the other diseases listed above, he or she will order additional tests that are more specific for those diseases or disorders. Because certain types of cancer treatments increase the uric acid in the body, the uric acid levels may be tested regularly to monitor the body’s reaction to chemotherapy.