Uric acidUrate · Serum urate
The end product of purine breakdown, and the substance behind gout.
Uric acid is what the body produces when it breaks down purines, compounds found in its own cells and in food. Most is cleared by the kidneys. Humans, unlike most mammals, lack the enzyme that would break it down further, so levels sit relatively high.
It matters because above a certain concentration it can crystallise in joints, which is what gout is. It also rises where the kidneys clear less of it, and is statistically associated with high blood pressure and metabolic problems, though whether it causes them is not settled.
In practice it is measured when gout is suspected and often appears on general panels. A raised value without symptoms is common and is not the same thing as having gout.