Uric Acid

What is Uric Acid?

Uric acid is a waste product from purine breakdown, not a direct measure of kidney filtration.

Uric acid forms when your body breaks down purines, compounds found in your own cells and in foods like red meat, organ meats, and certain seafood. About a third of your daily uric acid comes from what you eat; your body makes the rest on its own, continuously, as cells turn over. This is why uric acid sits in a different category from the other markers on this list. BUN, creatinine, cystatin C, and eGFR all measure how well your kidneys filter blood, directly or by estimation. Uric acid doesn't measure filtration at all. It measures a metabolic byproduct that the kidneys happen to be the main route for clearing. Roughly two-thirds of it leaves through the kidneys and into urine; the rest passes out through the gut, according to the NCBI StatPearls physiology review. A uric acid test can be normal even when filtration is declining, and it can run high in someone with completely normal kidney function, because diet, cell turnover, and certain medications all move the number independently of how well the kidneys filter. The kidneys still matter to the uric acid story, just not as the main character. Once filtered, the kidneys reabsorb about 90% of uric acid back into the blood at the proximal tubule, then secrete some of it again further along, according to StatPearls. That reabsorption step, not the filtration rate itself, is what medications like diuretics disrupt, which is one reason uric acid can climb on certain blood pressure drugs even when kidney filtration stays stable. When uric acid builds up faster than the body clears it, it can form needle-shaped crystals in and around joints, causing gout, or contribute to kidney stones, according to MedlinePlus. Many people carry high uric acid for years with no symptoms at all.

What changed recently

A meta-analysis published in October 2025, covering 22 observational studies and more than 235,000 people, found sugar-sweetened beverage intake associated with a 33% higher relative risk of hyperuricemia and a 21% higher relative risk of gout, with fructose specifically linked to a 66% higher relative gout risk and men showing a larger association than women (Frontiers in Nutrition, 2025). That sharpens the old, vaguer "high-fructose foods" advice into a specific, sourced beverage-and-fructose finding.

Separately, whether drug-lowering uric acid actually protects the heart or kidneys in people who don't have gout remains unsettled. The ALL-HEART trial, a UK randomized trial of more than 5,700 people with ischemic heart disease, found allopurinol did not reduce cardiovascular death, heart attack, or stroke compared with usual care (The Lancet, 2022), and a 2024 NIHR economic evaluation of the same trial data reached the same conclusion. That result feeds an active debate, reflected in a 2024 review in the Journal of Hypertension and a 2025 expert consensus update in the European Journal of Internal Medicine, over whether asymptomatic hyperuricemia, high uric acid without gout or kidney disease, should be treated at all before any symptoms appear. No guideline currently recommends treating it.

Tests often checked alongside this

• eGFR and creatinine — show whether reduced kidney filtration, rather than diet or purine turnover, could be contributing to a high result.
• BUN — another kidney-clearance marker doctors sometimes review together with uric acid, even though the two rise for different reasons.
• Fasting glucose or HbA1c — metabolic syndrome and insulin resistance are commonly linked with elevated uric acid in research.
• Lipid panel — often ordered alongside uric acid because both cluster with the same dietary and metabolic patterns.

What can affect this marker

Diet (purine-rich foods, sugar-sweetened beverages and fructose, alcohol, especially beer), body weight, dehydration, some diuretics and low-dose aspirin, and rapid cell turnover from conditions like chemotherapy or certain blood disorders can all move uric acid independent of kidney health. Because it's influenced by so many everyday factors, a single high reading calls for context and repeat testing more than immediate concern.

What to ask your doctor

• What's my lab's own reference range for this result, and where do I fall in it?
• Is this being checked because of a symptom, or as part of routine screening?
• If it's elevated, does it call for another test, a change in diet, or just monitoring over time?

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