Uric acid levels are typically 2.5–7.0 milligrams per deciliter (mg/dL) in males and 1.5–6.0 mg/dL in females. Low levels are rare, but high levels can lead to gout, kidney disease, and other health issues.
Uric acid is a waste product in the body. Sometimes, it builds up in the joints and tissues, causing various health problems.
Having some uric acid in the blood is normal. However, if uric acid levels go above or below a healthy range, this can result in health problems. High uric acid levels can increase the risk of gout and kidney stones.
If a person is passing too much uric acid, the levels in the urine will be high, and the levels in the blood will be low.
The following table gives low, normal, and high uric acid levels in the blood of males and females. All amounts are in milligrams per deciliter (mg/dL).
| Uric acid level | Males | Females |
|---|---|---|
| low | below 2.5 mg/dL | below 1.5 mg/dL |
| normal | 2.5–7.0 mg/dL | 1.5–6.0 mg/dL |
| high | above 7.0 mg/dL | above 6.0 mg/dL |
Purines are chemical substances that occur naturally in the body, as well as in some foods. When the body breaks down purines, uric acid is the waste product. The kidneys filter it from the blood and pass it out of the body in the urine.
However, uric acid can sometimes build up in the blood. Homeostasis is a term describing the body’s attempt to keep levels of various substances in the normal range. If the blood level is too high, excretion will increase. In the case of uric acid, most excretion is via the kidneys and urine. High levels of uric acid in the urine can lead to the formation of kidney stones.
The causes of high uric acid levels are not always clear. However, genetics and environmental factors, such as diet and health,
- drinking alcohol
- diabetes
- a diet that is high in foods and drinks that contain or raise purines, such as red meats and shellfish
- diuretics
- a diet high in fructose, present in sodas and most processed foods
- conditions that cause a rapid turnover of cells, such as blood cancers, psoriasis, and certain types of anemia
- certain immunosuppressant medications
A person with high or low uric acid levels may not always have symptoms. Symptoms may not appear until a person has had levels outside the normal range for an extended period, which can cause health problems.
Symptoms of gout, which high uric acid levels can cause, include:
- painful or swollen joints
- joints that feel warm to the touch
- shiny, discolored skin around the joints
Symptoms of a kidney stone, which high uric acid levels can also cause, include:
- back pain
- pain in the side
- frequent urination
- cloudy urine that smells unusual or contains blood
- nausea or vomiting
Low uric acid levels are less common than high ones. A person with low uric acid levels may urinate more than usual, which can cause dehydration if they are not drinking enough water.
Some medical conditions and treatments also have an association with high uric acid levels, particularly gout, kidney disease, and some cancer treatments.
Gout
Gout is a form of arthritis. The symptoms come and go, usually affecting just one joint.
In people with this condition, uric acid builds up in the joints and tissues,
Cancer treatment
When cells die, they release purines, which, when the body breaks them down, release uric acid into the blood.
Some cancer treatments, such as chemotherapy, cause cells in the body to die. Uric acid testing may be part of medical care for a cancer patient.
Kidney disease
The kidneys filter waste from the blood, including uric acid.
Kidney disease damages the kidneys and stops them from working. When this happens, waste products, including uric acid, can build up in the blood.
Fanconi syndrome
Having low uric acid levels is rare.
In Fanconi syndrome, uric acid is not reabsorbed at the typical levels, leading to excess urine and low serum levels.
Fanconi syndrome can cause a lack of energy, dehydration, and bone problems. A person with this condition will have low uric acid levels because too much of this substance is passing out of the body in the urine.
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A uric acid test measures the amount of uric acid in the blood or urine.
A person may need the test if they have gout symptoms or kidney stones or are undergoing cancer treatment. The test does not carry any risks.
A healthcare professional may take a small sample of blood with a needle or ask the person to collect their urine over 24 hours. Examining urine under a microscope will reveal uric acid crystals, especially if a person has kidney stones.
Doctors may sometimes also perform a joint aspiration, using a needle and syringe to remove a small amount of fluid from a swollen joint. The presence of uric acid crystals in the fluid indicates gout.
If the doctor needs more information to diagnose health problems related to uric acid, they may perform a physical examination and ask questions about the person’s medical history and current symptoms.
Sometimes, a person will have high uric acid levels but no symptoms of a medical condition. They are unlikely to need treatment unless they develop symptoms.
Certain foods contain purines, which create uric acid when the body breaks them down. Eating a diet that is too rich in purines can cause uric acid to build up in the blood.
It is not possible to avoid purines altogether because small amounts are present in many foods. However, a person can follow a low-purine diet and take other steps to help lower purine levels.
Foods and drinks that include moderate or high levels of purines include:
- alcohol
- bacon
- turkey
- veal
- organ meats
- shellfish
- trout
- haddock
- anchovies
- sardines
- herring
A person with gout may wish adopt a low-purine diet for the prevention of uric acid kidney stones.
Nonsteroidal anti-inflammatory drugs and steroids can reduce pain and inflammation,
Allopurinol (Zyloprim) can also
People can take steps to prevent gout flares. These include:
- avoiding alcohol
- reaching or maintaining a moderate weight
- protecting the joints with gentle, low impact exercise, such as walking, cycling, and swimming
A person who has gout usually needs a uric acid test every 6 months.
Keeping uric acid levels within a certain range can reduce pain, joint damage, and complications from gout.
When uric acid levels are very high, the kidneys can no longer process and excrete it effectively. As it accumulates in the body, uric acid crystals form. This can lead to gout, a painful joint inflammation.
A high intake of meat, seafood, and other foods containing purines can lead to high uric acid levels, but other causes exist. These include health conditions that affect purine metabolism, kidney disease, thyroid problems, cell breakdown due to a health condition or exercise, and medication use.
The two main symptoms are gout — which involves a hot and swollen joint, most commonly the big toe — and kidney stones, which can lead to pain, blood in the urine, nausea, and vomiting.
Uric acid is a waste product that can damage joints and tissue if it builds up too much in the body. People who have high uric acid levels for an extended period may develop health problems.
If a person has gout, they need to keep uric acid levels within a healthy range. This can improve the symptoms and reduce the risk of gout flare-ups.