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Unit Code 8440:
Uric Acid, Serum

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Useful For

Uric acid measurements are used in the diagnosis and treatment of

renal failure and monitoring patients receiving cytotoxic drugs and a

variety of other disorders, including gout, leukemia, psoriasis,

starvation and other wasting conditions.

Clinical Information

Uric acid is the final product of purine metabolism in humans. 

Purines, compounds that are vital components of nucleic acids

and coenzymes, may be synthesized in the body or they may be

obtained by ingesting foods rich in nucleic material (e.g. liver,

sweetbreads, etc.).  Approximately 75% of the uric acid excreted

is lost in the urine; most of the remainder is secreted into the

gastrointestinal tract, where it is degraded to allantoin and other

compounds by bacterial enzymes.

 

Asymptomatic hyperuricemia is frequently detected through

biochemical screening.  The major causes of hyperuricemia are

increased purine synthesis, inherited metabolic disorder, excess

dietary purine intake, increased nucleic acid turnover, malignancy,

cytotoxic drugs, and decreased excretion due to chronic renal failure

or increased renal reabsorption.  Long-term follow-up of these patients

is undertaken because many are at risk of renal disease that may

develop; few of these patients ever develop the clinical syndrome of gout.

 

Hypouricemia, often defined as serum urate less than 2.0 mg/dL, is much

less common than hypouricemia.  It may be secondary to severe

hepatocellular disease with reduced purine synthesis; defective renal

tubular reabsorption; overtreatment of hyperuricemia with allopurinol

and well as some cancer therapies (e.g. 6-mercaptopurine).

Reference Values

Males

      0-11 months:  Not established

      1-10 years:  2.4-5.4 mg/dL

      11 years:  2.7-5.9 mg/dL

      12 years:  3.1-6.4 mg/dL

      13 years:  3.4-6.9 mg/dL

      14 years:  3.7-7.4 mg/dL

      15 years:  4.0-7.8 mg/dL

      > or = 16 years:  3.7-8.0 mg/dL

Females

      0-11 months:  Not established

      1 year:  2.1-4.9 mg/dL

      2 years:  2.1-5.0 mg/dL

      3 years:  2.2-5.1 mg/dL

      4 years:  2.3-5.2 mg/dL

      5 years:  2.3-5.3 mg/dL

      6 years:  2.3-5.4 mg/dL

      7-8 years:  2.3-5.5 mg/dL

      9-10 years:  2.3-5.7 mg/dL

      11 years:  2.3-5.8 mg/dL

      12 years:  2.3-5.9 mg/dL

      > or = 13 years:  2.7-6.1 mg/dL

Interpretation

Hyperuricemia is most commonly defined by serum or plasma uric

acid concentrations greater than 8.0 mg/dL in males or greater than

6.1 mg/dL in females.

 

Cautions

The following drugs cause interference (falsely decreased levels)

at the therapeutic concentrations:  a-methyldopa, desferoxamine

and calcimdobesilate.

Clinical Reference

Tietz Textbook of Clinical Chemistry 4th edition, Edited by Burtis, Ashwood, and Bruns.  W.B. Saunders Company, Philadelphia, 24:803-807, 2006.  

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