Urate

Overview

Urate measures serum levels of uric acid, the final breakdown product of purine nucleotide metabolism excreted primarily by the kidneys. It serves as a major antioxidant in plasma but precipitates as monosodium urate crystals in supersaturated conditions, triggering gouty inflammation. Elevated levels indicate hyperuricemia, gout, tumor lysis syndrome, or renal impairment, while low levels occur in severe liver disease or xanthine oxidase deficiency; clinically useful for diagnosing gout, guiding urate-lowering therapy, and preventing uric acid nephropathy in high-risk patients.

Clinical Use Cases

  • Diagnosing gout and monitoring urate-lowering therapy efficacy.
  • Assessing tumor lysis syndrome risk in chemotherapy patients.
  • Evaluating uric acid nephrolithiasis and nephropathy.
  • Screening for inborn errors of purine metabolism (Lesch-Nyhan).
  • Stratifying cardiovascular and kidney disease risk.

Specimen Types

  • Serum.
  • Plasma (heparin).
  • Urine (24-hour for excretion studies).

Measurement Methods

  • Uricase enzymatic colorimetric assay.
  • Automated clinical chemistry analyzers.
  • High-performance liquid chromatography (HPLC).

Test Preparation and Influencing Factors

  • Fasting preferred; avoid high-purine foods and alcohol 24-48 hours prior.
  • Diuretics, low-dose aspirin, pyrazinamide elevate levels.
  • Allopurinol, probenecid, rasburicase rapidly lower levels.
  • Acute gout attacks cause transient elevations.
  • Dehydration concentrates serum urate.

Synonyms

  • Uric acid.
  • Serum urate.

Further Reading