What Is Uric Acid?

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Uric acid is produced when the body breaks down purines (purines provide part of the chemical structure of our genes). The two carbon-nitrogen ring bases, adenine and guanine, are purines. Purines serve as a form of energy for cells and are necessary for the production of DNA and RNA, proteins, starch, regulations of enzymes, and cell signaling.

Uric acid production is related to the synthesis of purines within the body and to extrinsic purine intake.

In other words, purines are found in all human tissue and they are found in many foods. When cells die in our body, purines are released. Uric acid is the end product or human purine metabolism. Elimination of uric acid from the body is dependent on excretion. It is that balance -- between uric acid production and excretion -- that determines the serum urate level (uric acid level in the blood).   

Serum Urate Levels

Most uric acid dissolves in the blood and travels to the kidneys to be excreted in the urine. Normally, people maintain a stable serum urate level between 4 and 6.8 mg/dl, as well as a total body uric acid of 1,000 mg. People who either produce too much uric acid or who are unable to eliminate enough uric acid have elevated serum urate levels. An elevated level of uric acid in the blood is known as hyperuricemia. Overproduction or under-excretion of uric acid, or a combination of both, can lead to hyperuricemia.

People with a high level of uric acid in the blood may develop kidney disease or gout via the development of crystals in the joints. Not every person with hyperuricemia develops gout though.

It's important to maintain a normal serum urate level. A blood test is one way to check your uric acid level. It can also be checked on a urine sample.

Ideally, serum uric acid should be 6.0 mg/dl or lower. A person who has a uric acid level of 6.8 mg/dl or higher is classified as having hyperuricemia.

Hyperuricemia can occur with various conditions, including:

  • acidosis
  • alcoholism
  • side effects of chemotherpy
  • gout
  • chronic gouty arthritis
  • diabetes
  • hypoparathyroidism
  • lead poisoning
  • leukemia
  • kidney disease
  • kidney failure
  • polycythemia vera
  • purine-rich diet
  • toxemia related to pregnancy

Low levels of uric acid may be associated with:

  • low purine diet
  • Fanconi syndrome
  • inappropriate antidiuretic hormone secretion
  • Wilson disease

The Bottom Line

It is important to know your uric acid level, no differently than it is important to know your cholesterol or blood glucose levels. People with a history of gout should have a uric acid level performed every 6 months to monitor that it remains under 6.0 mg/dl. Gout patients may require treatment with medications as well as lifestyle changes to keep uric acid at an appropriate level.

Sources:

Uric acid - blood. MedlinePlus. Updated 01/13/2016.
https://www.nlm.nih.gov/medlineplus/ency/article/003476.htm

About Uric Acid. Gout & Uric Acid Education Society.
http://gouteducation.org/patient/what-is-gout/uric-acid/

Kelley's Textbook of Rheumatology. Ninth edition. Elsevier. Chapter 94: Etiology and Pathogenesis of Hyperuricemia and Gout.

Purine and Pyrimidine Metabolism. Diffen. Accessed 01/23/16.
http://www.diffen.com/difference/Purines_vs_Pyrimidines

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