Uric acid measurements are used in the diagnosis and treatment of numerous renal and metabolic disorders, including renal failure, gout, leukemia, psoriasis, starvation or other wasting conditions, and of patients receiving cytotoxic drugs.
Uric Acid is the major product of purine catabolism in humans. Most uric acid formation occurs in the liver, and is eliminated via the kidney, with the body uric acid pool determined by the balance between synthesis and elimination. Hyperuricaemia is divided into primary and secondary classifications, involving either overproduction or reduced elimination. Primary hyperuricaemia is also known as the idiopathic or familial form. In the vast majority of affected cases, reduced tubular secretion of uric acid is responsible for the elevation in uric acid levels. Approximately 1% of patients with primary hyperuricaemia have an enzymatic defect in purine metabolism which results in overproduction of uric acid. Primary hyperuricaemia is associated with gout, Lesch-Nyhan syndrome, Kelley Seegmiller syndrome and increased phosphoribosyl pyrophosphate synthase activity. Secondary hyperuricaemia may be caused by increased nutritional purine uptake, associated with increased uric acid excretion in the urine. Secondary hyperuricaemia is associated with numerous conditions including renal insufficiency, myeloproliferative diseases, haemolytic diseases, psoriasis, polycythemia vera, type I glycogen storage disease, excess alcohol consumption, lead intoxication, a purine-rich diet, fasting, starvation and chemotherapy.
Hypouricaemia may result from decreased uric acid production, such as occurs in hereditary xanthinuria, hereditary purine nucleoside phosphorylase deficiency and allopurinol therapy. Hypouricaemia may also be due to increased renal uric acid excretion, which may occur in malignant diseases, AIDS, Fanconi syndrome, diabetes mellitus, severe burns and hypereosinophilic syndrome. In addition, hypouricaemia may result from treatment with uricosuric agents and ingestion of X-ray contrast media. Quantitation of urinary uric acid excretion may assist in the selection of appropriate treatment for hyperuricaemia, providing an indication of whether patients should be treated with uricosuric drugs to enhance renal excretion, or allopurinol to supress purine synthesis.
REFERENCE INTERVALS Serum (reference range according Tietz) Male 208.3 – 428.4 μmol/L (3.5 – 7.2 mg/dL) Female 154.7 – 357.0 μmol/L (2.6 – 6.0 mg/dL)
SI units Conversion Calculator. Convert Uric Acid level to mmol/L, µmol/L, mg/dL, mg/100mL, mg%, mg/L, µg/mL. Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for Uric Acid unit conversion to mmol/L, µmol/L, mg/dL, mg/100mL, mg%, mg/L, µg/mL.