Elevated uric acid: Elevations of uric acid occur with increased purine synthesis, inherited metabolic disorders, excess dietary purine intake, increased nucleic acid turnover, malignancy, cytotoxic drugs, decreased excretion due to chronic renal failure, and increased renal reabsorption.

Drugs: Drugs causing increased uric acid concentration include diuretics, pyrazinamide, ethambutol, and nicotinic acid.

Endocrine: Hypothyroidism, hypoparathyroidism, hyperparathyroidism, pseudohypoparathyroidism, diabetes insipidus of nephrogenic type, and Addison disease can cause uric acid elevation. Lead poisoning from paint, batteries, and moonshine can cause elevated uric acid. Toxemia of pregnancy, diet, weight loss, fasting, or starvation can elevate uric acid levels.

Decreased uric acid: Drugs bearing a relationship to low serum uric acid levels include aspirin (high doses), x-ray contrast agents, glyceryl guaiacolate, allopurinol corticosteroids, and probenecid. Massive doses of vitamin C increase urine uric acid secretion, lowering serum uric acid. Poor dietary intake of purines and protein can decrease serum uric acid. Diabetes, Fanconi syndrome, Wilson’s disease, cystinosis, galactosemia, hypophosphatemia, heavy metal poisoning, malignant neoplasms, hypereosinophilic syndrome, and Xanthinuria (deficiency of xanthine oxidase) can lower serum uric acid. Hypouricemia is reported with acute intermittent porphyria and severe liver disease (especially obstructive biliary disease). Isolated defects in the tubular transport of uric acid have been associated with increased renal clearance of urate, hypouricemia, hypercalciuria, and decreased bone density.