Uric acid is the major end product of nitrogen metabolism in avian species. It constitutes approximately 60 to 80% of the total nitrogen excreted in avian urine and is secreted actively by the renal tubules. Measurement of plasma or serum uric acid is used as an index of renal function in birds. Increases in uric acid concentration are seen in the following situations:
- Artifact: Uric acid can also be falsely increased in samples from toe-nail clippings because of fecal urate contamination.
- Post-prandial: Uric acid concentrations will increase after a meal in carnivorous birds.
- Renal disease: Concentrations increase when the kidney has lost >70% of its functional capacity.