Synonym/Acronym
urate.
Rationale
To monitor uric acid levels during treatment with cytotoxic drugs for gout, leukemia, liver damage, psoriasis, renal function, and other conditions; to monitor patients being evaluated for starvation and other wasting conditions; to evaluate for kidney stones, particularly uric acid stones; and to assess the effectiveness of therapeutic interventions.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction. For urine studies, usually a 24-hr urine collection is ordered. As appropriate, provide the required urine collection container and specimen collection instructions.
Normal Findings
Method: Spectrophotometry.
| Blood |
|---|
| Age | Conventional Units | SI Units (Conventional Units × 0.059) |
|---|
| 1–30 days | | |
| Male and female | 2–6.2 mg/dL | 0.11–0.37 mmol/L |
| Child | | |
| Male and female | 2.5–5.5 mg/dL | 0.15–0.32 mmol/L |
| Adult | | |
| Male | 4–8 mg/dL | 0.24–0.47 mmol/L |
| Female | 2.5–7 mg/dL | 0.15–0.41 mmol/L |
| Adult older than 60 yr | | |
| Male | 4.2–8.2 mg/dL | 0.25–0.48 mmol/L |
| Female | 3.5–7.3 mg/dL | 0.21–0.43 mmol/L |
Therapeutic target for patients with gout: Less than 6 mg/dL (SI: Less than 0.4 mmol/L).
| Urine |
|---|
| Gender | Conventional Units | SI Units (Conventional Units × 0.0059) |
|---|
| Male | 200–1,000 mg/24 hr | 1.48–4.72 mmol/24 hr |
| Female | 250–750 mg/24 hr | 1.48–4.43 mmol/24 hr |
Values reflect average purine diet.
Blood
- Greater than 13 mg/dL (SI: Greater than 0.8 mmol/L)
Timely notification to the requesting health-care provider (HCP) of any critical findings and related symptoms is a role expectation of the professional nurse. A listing of these findings varies among facilities.
Symptoms of acute renal dysfunction and/or chronic kidney disease associated with hyperuricemia include altered mental status, nausea and vomiting, fluid overload, pericarditis, and seizures. Prophylactic measures against the development of hyperuricemia should be undertaken before initiation of chemotherapy. Possible interventions include discontinuing medications that increase serum urate levels or produce acidic urine (e.g., thiazides and salicylates); administration of fluids with sodium bicarbonate as an additive to IV solutions to promote hydration and alkalinization of the urine to a pH greater than 7; administration of allopurinol 1 to 2 days before chemotherapy; monitoring of serum electrolyte, uric acid, phosphorus, calcium, and creatinine levels; and monitoring for ureteral obstruction by urate calculi using computed tomography or ultrasound studies. Possible interventions for advanced renal insufficiency and subsequent chronic kidney disease may include peritoneal dialysis or hemodialysis.
(Study type: Blood collected in a gold-, red-, red/gray-, or green-top [heparin] tube; related body system: Multisystem [metabolic disorders] and Urinary system. Note: Rasburicase will rapidly decrease uric acid in specimens left at room temperature. If patients are receiving this medication, collect the blood sample in a prechilled green-top [heparin] tube and transport in an ice slurry.)
Uric acid 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 purine intake from dietary sources such as organ meats (e.g., liver, thymus gland and/or pancreas [sweetbreads], kidney), legumes, and yeasts. Uric acid is filtered, absorbed, and secreted by the kidneys and is a common constituent of urine. Serum urate levels are affected by the amount of uric acid produced and by the efficiency of renal excretion. Values can vary based on diet, gender, body size, level of exercise, level of stress, and regularity in consumption of alcohol. Elevated uric acid levels can indicate conditions of critical cellular injury or destruction; hyperuricemia has an association with gout, hypertension, hypertriglyceridemia, kidney stones, obesity, myocardial infarct, renal disease, and diabetes. Rasburicase is a medication used in the treatment and prevention of acute hyperuricemia related to tumor lysis syndrome in children and for leukemias and lymphomas related to the toxic effects of chemotherapy. Rasburicase is a recombinant form of uricase oxidase, an enzyme that converts uric acid to allantoin, a much more soluble and effectively excreted substance than uric acid.
The ratio of 24-hr urine uric acid to creatinine can be used as a test for detection of Lesch-Nyhan syndrome, a disorder of uric acid metabolism associated with absence of the enzyme hypoxanthine-guanine phosphoribosyltransferase. The ratio in healthy patients is reported to range from 0.21 to 0.59. Patients with partial or complete enzyme deficiency can have ratios from 2 to 5. Urine uric acid levels are also used to assist in the diagnosis of gout and kidney stones.
Increased In
Blood
Conditions that result in high cellular turnover release nucleic acids into circulation, which are converted to uric acid by the liver. Note:* Some instances of increased uric acid may occur in both blood and urine, assuming normal glomerular filtration rate.
- Acute tissue destruction as a result of starvation or excessive exercise (related to cellular destruction)
- Administration of uricosuric drugs*
- Chemotherapy and radiation therapy* (related to high cellular turnover)
- Chronic lead toxicity (cellular destruction related to hemolysis)
- Diabetes (decreased renal excretion results in increased blood levels)
- Disorders of purine metabolism*
- Down syndrome
- Eclampsia
- Excessive dietary purines* (purines are nucleic acid bases converted to uric acid by the liver)
- Glucose-6-phosphate dehydrogenase deficiency (cellular destruction related to hemolysis)
- Gout* (usually related to excess dietary intake)
- Heart failure (related to cellular destruction)
- HELLP syndrome of pregnancy; variant of pre-eclampsia (hemolysis, elevated liver enzymes, low platelet count)
- Hyperparathyroidism
- Hypertension (related to effects on renal excretion)
- Hypoparathyroidism (related to disturbances in calcium and phosphorus homeostasis)
- Lactic acidosis (cellular destruction related to shock)
- Lead poisoning* (cellular destruction related to hemolysis)
- Lesch-Nyhan syndrome (related to disorder of uric acid metabolism)
- Neoplastic disorders, such as leukemia, lymphosarcoma, and multiple myeloma* (related to increased cell turnover)
- Pernicious anemia* (cellular destruction related to hemolysis)
- Polycystic kidney disease (related to decreased renal excretion, which results in increased blood levels)
- Polycythemia vera* (related to increased cellular destruction)
- Psoriasis
- Rhabdomyolysis (related to increased cellular destruction)
- Sickle cell anemia* (cellular destruction related to hemolysis)
- Substance use disorder—alcohol (related to increased production)
- Tumors(related to high cell turnover)
- Type III hyperlipidemia
Urine
- Administration of uricosuric drugs*
- Chemotherapy and radiation therapy* (related to high cellular turnover)
- Disorders associated with impaired renal tubular absorption, such as Fanconi syndrome and Wilson disease
- Disorders of purine metabolism*
- Excessive dietary intake of purines*
- Gout*
- Kidney stone formation (related to increased urinary excretion as sodium urate)
- Lead poisoning* (cellular destruction related to hemolysis)
- Lesch-Nyhan syndrome (related to increased urinary excretion due to enzyme deficiency)
- Neoplastic disorders, such as leukemia, lymphosarcoma, and multiple myeloma* (related to increased cell turnover)
- Pernicious anemia* (related to increased cell turnover)
- Polycythemia vera* (related to increased cell turnover)
- Sickle cell anemia* (related to increased cell turnover)
Decreased In
Blood
- Fanconi syndrome (related to increased renal excretion)
- Low-purine diet (related to insufficient nutrients for liver to synthesize uric acid)
- Severe liver disease (uric acid synthesis occurs in the liver)
- Wilson disease (affects normal liver function and is related to impaired tubular absorption)
Urine
- Chronic alcohol ingestion (related to decreased excretion)
- Hypertension (related to decreased excretion)
- Severe kidney damage (possibly resulting from chronic glomerulonephritis, collagen disorders, diabetic glomerulosclerosis, lactic acidosis, ketoacidosis, or alcohol misuse)
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this test can assist in diagnosing gout and assessing kidney function.
- Explain that a blood or urine sample is needed for the test. Information regarding urine specimen collection is presented with other general guidelines in Appendix A: Patient Preparation Specimen Collection.
Potential Nursing Actions
- Include on the collection container’s label the urine total volume, test start and stop times/dates, and any medications that may interfere with test results.
After the Study: Implementation & Evaluation Potential Nursing Actions
Treatment Considerations
- Increased urine uric acid levels may be associated with the formation of kidney stones. For additional information, refer to the study titled “Kidney Stone Evaluation.” Educate the patient, if appropriate, on the importance of drinking a sufficient amount of water when kidney stones are suspected.
Safety Considerations
- Interventions/actions include the following: Recognize that confusion can occur due to altered fluid and electrolytes as well as renal or hepatic disease. Correlate confusion with the need to reverse altered electrolytes and evaluate medications. Prevent falls and injury through appropriate use of postural support, bed alarm, or restraints. Consider pharmacological interventions.
Nutritional Considerations
- Interventions/actions include the following: Correlate baseline nutritional intake with medical status. Facilitate nutritional interventions that work within the disease parameters. Assess nutritional requirements and seek consultation with a registered dietitian. Consider individual and cultural food preferences. Collaborate with HCP, pharmacist, and clinical dietitian in consideration of enteral and parenteral nutrition.
- Increased uric acid levels may be associated with gout. Nutritional therapy may be of value to those with gout.
- Foods high in oxalic acid should be avoided. These include caffeinated beverages, raw blackberries, gooseberries, plums, whole-wheat bread, beets, carrots, beans, rhubarb, spinach, dry cocoa, and Ovaltine.
- Foods high in purines should be restricted. These include some fish, including anchovies, sardines, herring, mussels, codfish, scallops, trout, and haddock. Meats, such as bacon, goose, turkey, veal, venison, and organ meats (hearts, kidneys, liver, oxtail, spleen, sweetbreads, and ox/cow lungs). Sometimes a low-purine or purine-restricted diet for treatment of gout may not be instituted because medications can control the condition easily and effectively.
Clinical Judgement
- Consider how to stress the value of nutritional therapy in kidney and overall health.
Follow-Up Evaluation and Desired Outcomes
- Acknowledges the value of lifestyle alterations that may improve health.