Uric acid test explained (UA)

Uric acid is formed when the body breaks down purines — compounds present in the DNA of cells and in many foods (meat, organ meats, seafood, alcohol, especially beer). Most of it is removed by the kidneys, the rest by the bowel. When too much is produced, or the kidneys remove too little, the concentration in the blood rises (hyperuricaemia). If a high concentration persists for a long time, uric acid can crystallise in the joints — this is gout, which most often starts in the painful joint of the big toe — or in the kidneys, forming stones. Raised uric acid without symptoms is common and is not always treated in itself, but it is associated with metabolic syndrome, raised blood pressure and kidney disease. The test is done on blood, and in the case of kidney stones also on urine collected over a full day.

• When gout is suspected — with acute, painful swelling of a joint (often a toe)
• With kidney stones, or when they are suspected
• To monitor kidney function, especially in kidney disease
• Before and during chemotherapy — uric acid rises quickly as tumour cells break down
• As part of assessing metabolic syndrome — with excess weight, raised blood pressure or diabetes

Raised uric acid (hyperuricaemia) is most often linked to purine-rich food, alcohol, fructose, excess weight, dehydration and kidney disease, when too little of the acid is removed. Other causes are hypothyroidism, hyperparathyroidism, psoriasis, blood disorders, chemotherapy and some medicines. Over a long time it can lead to gout and kidney stones. There are often no symptoms; a gout attack shows as sudden, very painful swelling and reddening of a joint, often a toe, and signs of kidney stones are pain in the side and blood in the urine.

• Purine-rich food, alcohol, fructose
• Excess weight and obesity
• Kidney disease and kidney failure — the acid is removed too slowly
• Dehydration
• Some medicines, especially diuretics
• Hypothyroidism, hyperparathyroidism
• Psoriasis
• Blood disorders — leukaemia, polycythaemia vera; chemotherapy
• Intense physical exertion, acidosis, pregnancy complications, vitamin B12 deficiency

What to discuss with a doctor: whether there have been gout attacks or kidney stones — whether treatment is needed depends on that; creatinine and GFR, which show kidney function; diet, alcohol and sweet drinks containing fructose; medicines that can raise the acid; and other markers of metabolic syndrome — glucose, lipids such as triglycerides, and blood pressure.

Low uric acid is less common and usually has no significance. The causes are a diet low in purines, some medicines (including some of those that lower cholesterol, and gout medicines), rare inherited metabolic disorders, Fanconi syndrome and HIV infection.

• A diet low in purines
• Some medicines — some of those that lower cholesterol, and gout medicines that increase removal of the acid
• Inherited metabolic disorders
• Fanconi syndrome — a disorder of the kidney tubules
• HIV infection

What to discuss with a doctor: the medicines being taken, which are the most common cause; and, if there is no clear cause, tests of kidney tubule function.

At the Medicina practica laboratory a uric acid test costs from €6.50 (September 2026 pricing). When gout is suspected, a family doctor usually orders the test free of charge. Related pages: creatinine, GFR, glucose, triglycerides and CRP.