Chemistry / Electrolytes
Uric acid
End-product of purine catabolism; elevated in gout, tumor lysis, and metabolic syndrome.
Sample
Serum
Clinical reference range
3.4 to 7 mg/dL
Adult male · Female 2.4–6.0
Conv: 3.4–7 mg/dLFunc: 3.5–5.5 mg/dL
Biology
What it measures
Xanthine oxidase generates uric acid from xanthine. Humans lack uricase, so we accumulate it relative to other mammals.
Clinical use
Why we order it
Gout diagnosis/monitoring (target <6 mg/dL on therapy; <5 with tophi). Tumor lysis syndrome.
Lens · Clinical
Interpretation by lens
Clinical interpretation
ULT (allopurinol/febuxostat) target: serum urate <6 mg/dL (<360 µmol/L); <5 mg/dL with tophi.
Differential
Causes of abnormal values
Causes of HIGH
- ↑Gout
- ↑Renal insufficiency
- ↑Diuretics (thiazides, loop)
- ↑Metabolic syndrome / fructose intake
- ↑Tumor lysis
- ↑Psoriasis
Causes of LOW
- ↓SIADH
- ↓Fanconi syndrome
- ↓Allopurinol / uricosurics