Urine Uric Acid

Function

Uric acid is the end-product of the metabolic breakdown of purines, which are nitrogenous bases found in DNA and RNA, as well as in many foods. The kidneys are responsible for excreting about two-thirds of the uric acid produced by the body. A 24-hour urine uric acid test measures the total amount of this substance cleared by the kidneys over a full day, providing a clearer picture of purine metabolism than a single random sample.

Why it is Ordered

Physicians order this test primarily to investigate the cause of recurrent kidney stones (urolithiasis). High levels of uric acid in the urine (hyperuricosuria) can lead to the formation of uric acid stones or contribute to calcium oxalate stones. It is also used to differentiate between 'over-producers' and 'under-excretors' of uric acid in patients with Gout, which helps in selecting the appropriate medication (e.g., Allopurinol vs. Probenecid). Additionally, it monitors patients undergoing chemotherapy to prevent Tumor Lysis Syndrome.

Associated Conditions

• Gout: A form of inflammatory arthritis caused by urate crystal deposition.
• Kidney Stones: Specifically uric acid lithiasis.
• Lesch-Nyhan Syndrome: A rare genetic disorder causing massive uric acid overproduction.
• Myeloproliferative Disorders: Such as leukemia or lymphoma, where high cell turnover increases purine breakdown.