40. Laboratory assessment of increased serum uric acid levels

Uric acid (or urate) is a metabolic breakdown product of purines. Purines are metabolised to xanthine and then to uric acid by xanthine oxidase. Deposition of uric acid crystals in joints is the driving mechanism in attacks of gout. Deposition of uric acid crystals in the kidney can cause uric acid nephropathy.

Elevated uric acid is seen in gout, but is also seen in tumour lysis syndrome, preeclampsia, obesity, and hypertension. It's important to note that normal plasma uric acid level during a suspected gout attack does not rule out gout; uric acid levels are usually normal during the attack. The normal range is approx 200 - 500 µmol/L.