This test measures the concentration of uric acid (the final salt of purine metabolism) in the blood serum. Purines are compounds found in some foods (such as red meat and seafood) and are also produced within the body from the breakdown of cells. Uric acid levels rise when production (from food or within the body) increases or excretion via the kidneys decreases. Chronically elevated levels (hyperuricemia) increase the risk of sodium urate crystals depositing in the joints, causing gout, and in the kidneys, causing stones or nephropathy.