Unit Code 460081:
Uric Acid, Serum
Useful For
Uric acid measurements are used in the diagnosis and treatment
of renal failure, monitoring patients receiving cytotoxic drugs, and
in 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 materal (e.g., liver,
sweetbreads). 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 necessary because many are at
risk of developing renal disease. 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 hyperuricemia. It may be secondary
to severe hepatocellular disease with reduced purine synthesis,
defective renal tubular reabsorption, over-treatment of hyperuricemia
with allopurinol, and some cancer therapies (e.g., 6-mercaptopurine).
Reference Values
Results reported in mg/dL
Males
0-11 months: Not established
1-10 years: 2.4-5.4
11 years: 2.7-5.9
12 years: 3.1-6.4
13 years: 3.4-6.9
14 years: 3.7-7.4
15 years: 4.0-7.8
> or = 16 years: 3.7-8.0
Females
0-11 months: Not established
1 year: 2.1-4.9
2 years: 2.1-5.0
3 years: 2.2-5.1
4 years: 2.3-5.2
5 years: 2.3-5.3
6 years: 2.3-5.4
7-8 years: 2.3-5.5
9-10 years: 2.3-5.7
11 years: 2.3-5.8
12 years: 2.3-5.9
> or = 13 years: 2.7-6.1
Interpretation
Hyperuricemia is most commonly defined by serum or plasma
uric acid concentrations >8.0 mg/dL in males or >6.1 mg/dL in females.
Cautions
The following drugs cause interference (falsely decreased levels)
at therapeutic concentrations: a-methyldopa, desferoxamine, and
calciumdobesilate.
Clinical Reference
Tietz Textbook of Clinical Chemistry 4th edition. Edited by Burtis, Ashwood,
and Bruns. WB Saunders Company, Philadelphia, 24:803-807, 2006
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