Uric Acid

Uric acid (urate) is the end product of purine metabolism. Purines are important constituents of nucleic acids; purine turnover occurs continuously in the body, producing substantial amounts of uric acid even in the absence of dietary purine (e.g., meats, legumes, yeasts) intake. Most uric acid is synthesized in the liver and excreted by the kidneys. Serum urate levels are affected by the amount of uric acid produced as well as by the efficiency of renal excretion.

Both gout and urate renal calculi (kidney stones) are associated with elevated uric acid levels. Other disorders and drugs associated with altered uric acid levels are listed in Table 5-9.

Reference Values ⬆ ⬇

	Conventional Units	SI Units
Children	2.5-5.5 mg/dL	0.15-0.33 mmol/L
Men	4.0-8.5 mg/dL	0.24-0.51 mmol/L
Women	2.7-7.3 mg/dL	0.16-0.43 mmol/L
Critical values	>12 mg/dL	0.71 mmol/L

Interfering Factors ⬆ ⬇

Therapy with drugs known to alter uric acid levels (see Table 5-9), unless the test is being conducted to monitor such drug effects

Indications ⬆ ⬇

Family history of gout (autosomal dominant genetic disorder) or signs and symptoms of gout, or both, with the disorder indicated by elevated levels
Known or suspected renal calculi, to determine the cause
Signs and symptoms of disorders associated with altered uric acid levels (see Table 5-9)
Monitoring for the effects of drugs known to alter uric acid levels (see Table 5-9), either as a side effect or as a therapeutic effect
Evaluation of the extent of tissue destruction in infection, starvation, excessive exercise, malignancies, chemotherapy, or radiation therapy
Evaluation of possible liver damage in eclampsia, as indicated by elevated levels

Care Before Procedure ⬆ ⬇

Nursing Care Before the Procedure

Client preparation is the same as that for any study involving the collection of a peripheral blood sample (see Appendix I).

Some laboratories require an 8-hour fast from food before the test.

Procedure ⬆ ⬇

A venipuncture is performed and the sample collected in a red-topped tube. The sample should be handled gently to avoid hemolysis and sent promptly to the laboratory.

Care After Procedure ⬆

Nursing Care After the Procedure

Care and assessment after the procedure are the same as for any study involving the collection of a peripheral blood sample.

Resume foods withheld before the test.
Abnormal values: Note and report increased level. Assess for symptoms associated with renal stones and joint pain. Prepare to administer ordered medications (allopurinol, probenecid, nonsteroidal anti-inflammatory analgesics). Increase fluid intake. Instruct client to avoid high-purine fluids and foods (sardines, organ meats, legumes, alcohol, caffeine-containing beverages).
Critical values: Notify the physician immediately if levels are greater than 12 mg/dL.