Uric acid is a waste product formed when the body breaks down purines, substances found in many foods and produced naturally during cell turnover. Most uric acid dissolves in the blood and passes out through the kidneys, but when production outpaces clearance, levels rise.
Elevated uric acid is associated with cardiovascular disease, metabolic syndrome, hypertension, and kidney stones, and at higher levels causes gout. It's a marker many longevity frameworks track as a metabolic stress signal, particularly because fructose metabolism drives it up independent of calorie intake. Sex-stratified optimal ranges apply: men typically run higher than women due to hormonal differences in renal clearance.
Optimal Uric Acid: 3.5-5.9 mg/dL.
Typically re-tested every 10 weeks.
This page is educational and is not medical advice.
Uric acid is the final waste product of purine metabolism in humans, and the blood test measures how much of it is circulating at the moment the sample is drawn.
Purines come from two places. Most are recycled from your own cells as DNA and RNA are broken down and rebuilt, and a smaller share arrives in food. The breakdown pathway runs from hypoxanthine to xanthine to uric acid, and the enzyme xanthine oxidase catalyses the last two steps, which is why research on xanthine oxidase inhibition looks at its effect on circulating uric acid[1].
Most mammals carry an enzyme called uricase that converts uric acid into a more soluble compound. Humans do not, so uric acid is the end of the line and it accumulates in blood at higher concentrations than in most other species. That has a flip side. Uric acid is one of the more abundant antioxidants in human plasma, and studies of antioxidant defence in metabolic disease measure it alongside other antioxidant markers for that reason[2].
Clearance is mostly renal. The kidneys filter uric acid and then reabsorb a large part of it through dedicated transporters before excreting the remainder, and the gut handles the rest. Because reabsorption is so active, small shifts in kidney handling move the blood level more than most dietary changes do. In practice, a high result usually reflects reduced excretion more than excess production, although both can contribute.
Uric acid matters because it sits at the intersection of joint health, kidney function and cardiometabolic risk, and it is cheap to measure on a routine blood chemistry panel.
The most direct consequence of a persistently raised level is crystal formation. When blood concentrations exceed the point at which urate stays dissolved, monosodium urate crystals can deposit in joints and soft tissue, which is the mechanism behind gout and the reason clinicians use the blood level as one input when evaluating a painful joint[3]. Crystals can also form in the urinary tract as uric acid stones.
Beyond joints, uric acid has been studied for decades as a cardiovascular marker, and reviews describe its association with hypertension, endothelial function and vascular disease, while noting that association is not the same as cause[4]. The kidney relationship runs in both directions. A systematic review and meta-analysis reported that hyperuricaemia is associated with an increased risk of acute kidney injury[5], and a separate study found that serum uric acid may help predict progressive acute kidney injury after open heart surgery[6]. Whether lowering urate protects the kidney over time is still debated, and a meta-analysis of urate lowering therapy in chronic kidney disease examined exactly that question[7].
Uric acid also tends to travel with insulin resistance, central adiposity, high triglycerides and raised blood pressure. On its own, a single number proves nothing. Read next to glucose, kidney and inflammation markers, it becomes a useful early signal that metabolic load is building.
Most laboratories report a typical adult reference range of 2.5 to 7 mg/dL, and FitScript uses tighter optimal targets that differ by sex.
| Group | Typical lab reference range | FitScript optimal range |
|---|---|---|
| Adults (general) | 2.5 to 7 mg/dL | 3.5 to 5.9 mg/dL |
| Men | 3.5 to 7.2 mg/dL | 3.5 to 5.9 mg/dL |
| Women | 2.5 to 6.2 mg/dL | 2.5 to 5 mg/dL |
Uric acid runs higher in men than in women. In healthy adults the gap narrowed after 50, as women's levels rose, and a study of adults over 70 found the same pattern.[13][14]
| Sex | Age | Reference range (μmol/L) |
|---|---|---|
| Men | 18 to 49 | 284.3 to 587.4 |
| Men | 50 to 94 | 273.7 to 578.0 |
| Women | 18 to 49 | 199.8 to 437.9 |
| Women | 50 to 94 | 206.7 to 471.2 |
In adults 70 and over the second study reports 0.24 to 0.54 mmol/L in men and 0.19 to 0.48 mmol/L in women.[14] US labs usually report mg/dL, so your own lab's printed range is the one to read your result against.
Reference ranges vary by laboratory, age and sex, so always read your result against the range printed on your own report. Some labs report uric acid in micromoles per litre rather than milligrams per decilitre, and the numbers look very different even though the measurement is the same.
FitScript's optimal ranges are optimization targets, not diagnostic cut-offs. A result inside the standard lab range but outside the optimal range is not a disease, and a result outside the standard range is not a diagnosis either. Women generally run lower than men until menopause, after which levels tend to rise and the gap narrows. Children typically sit lower still, which is one more reason to use the range supplied with your own panel.
One clinically important detail. The concentration at which urate stops staying dissolved in body fluid is a physical property, not a statistical range, which is why a value can be inside a lab's reference interval and still be relevant to someone with a history of gout. That judgement belongs to a clinician who knows your history.
A high result means more urate is circulating than your kidneys and gut are clearing, and it is worth discussing with a clinician rather than interpreting alone.
What people report. Most of the time, nothing at all. Raised uric acid is usually silent and is found incidentally on a routine panel. When symptoms do appear, the classic presentation is a sudden, severe, hot and swollen joint, often starting at night and often at the base of the big toe, which is the picture clinicians work through when evaluating crystal arthritis[3]. Uric acid stones can cause flank or groin pain and blood in the urine. Long-standing deposits can form firm nodules called tophi under the skin.
Common reasons it runs high. Reduced renal excretion is the most frequent driver, which is why kidney function and uric acid are read together. Other contributors include dehydration, regular alcohol intake (beer in particular, because it is also a purine source), high intakes of fructose-sweetened drinks, diets heavy in organ meat, red meat and shellfish, excess body fat and insulin resistance, rapid weight loss or prolonged fasting, and certain medications discussed below. Conditions involving rapid cell turnover release large amounts of purine, and the interaction between high turnover states and impaired kidney function is a recognised clinical concern in haematology and oncology care[8]. Psoriasis and some thyroid disorders are also associated with higher levels.
What it can mean over time. Persistently raised urate is associated with recurrent gout flares, joint damage, uric acid stones and progression of chronic kidney disease, and it has been linked with acute kidney injury risk in pooled analyses[5]. It is also one of the markers that clusters with cardiovascular risk[4]. A single elevated value in an otherwise healthy person is a prompt to retest under standard conditions and look at the rest of the panel, not a verdict. A markedly high value, or any elevated value with joint pain, reduced urine output or known kidney disease, is worth discussing with a clinician promptly.
A low result means less urate is circulating than expected, usually because production is reduced or the kidneys are excreting more than usual, and it is far less often flagged than a high result.
What people report. Typically nothing. Low uric acid rarely produces symptoms by itself. Where an inherited form of renal hypouricaemia is present, clinicians have described episodes of acute kidney injury following intense exercise, and kidney stones can occur, so a persistently low value in someone who gets unexplained post-exercise illness deserves a proper look.
Common reasons it runs low. A genuinely low purine and low protein intake will pull the number down. So will medications and conditions that increase urinary urate loss, including proximal tubule dysfunction, and dilutional states such as the syndrome of inappropriate antidiuretic hormone. Advanced liver disease can reduce production, since the liver is where most uric acid is made. Pregnancy is associated with lower values in early and mid gestation. Inherited xanthinuria, a rare deficiency of xanthine oxidase, produces very low levels, consistent with the enzyme's central role in the pathway[1].
What it can mean over time. Because uric acid contributes meaningfully to the antioxidant capacity of plasma, a very low level has been discussed as a possible marker of reduced antioxidant defence[2], and research on exercise-induced oxidative stress routinely tracks antioxidant status alongside markers of muscle stress[9]. In practice, a mildly low result in someone eating a plant-heavy diet is usually unremarkable, while a very low result, or one accompanied by abnormal kidney, liver or electrolyte markers, is worth reviewing with a clinician.
Uric acid is more movable than most chemistry markers, so testing conditions, medications and recent habits all deserve attention before you read too much into a single value.
Testing conditions. Draw your sample under the same conditions each time if you want results you can compare. A large purine-rich meal, heavy alcohol the night before, or dehydration can shift the number. Strenuous exercise shortly before a draw can also move it, and studies examining exercise alongside xanthine oxidase activity have looked at exactly this interaction[1]. Fasting state, time of day and acute illness all add noise. Prolonged fasting or a sharp calorie deficit tends to raise urate temporarily through competition for renal excretion.
Medications. Urate lowering medicines work either by reducing production through xanthine oxidase inhibition or by increasing urinary excretion, and their effect on kidney outcomes in chronic kidney disease has been assessed in a systematic review and meta-analysis[7]. No dosing or administration guidance belongs on a page like this. A licensed provider evaluates whether any of these is appropriate for you, and no prescribed medication should be started, stopped or changed without that review.
Habits and supplements. Alcohol, sugar-sweetened and fructose-heavy drinks, and very high purine intakes are the dietary levers with the clearest association. Hydration, body composition and insulin sensitivity matter at least as much. Antioxidant supplements have been studied for their effect on urate in kidney disease populations, with mixed and preliminary findings[10]. Treat supplement claims in this space with caution.
Uric acid is measured on a standard blood chemistry draw, the same sample that carries kidney and metabolic markers, and it is one of the biomarkers included in FitScript's testing, which covers 150+ biomarkers tested per year.
A single value is a snapshot. The useful signal comes from repeat measurement under consistent conditions, read next to kidney filtration markers, glucose regulation and inflammation. Atlas, FitScript's AI health advisor, reads uric acid in that context rather than in isolation and writes your FitScript from the full set of results, so a borderline value is interpreted alongside what the rest of your biology is doing rather than treated as a standalone flag.
What testing can show is the trend, the size of the change and whether the markers that usually move with urate are moving too. What testing cannot do is diagnose gout, explain a painful joint or decide that treatment is needed. Gout is a clinical diagnosis supported by examination and, where appropriate, joint fluid analysis[3]. If a result suggests that medication should be considered, a licensed provider reviews your history, your kidney function and your other medications and decides whether any treatment is appropriate. Bring your results and any symptoms to a clinician or licensed provider who can see your full picture.
Read uric acid next to kidney, metabolic and inflammatory markers, because that is where its meaning comes from.
Start with kidney clearance. eGFR estimates filtration rate and is the single most useful companion marker, since reduced filtration is a common reason urate accumulates. Creatinine feeds that estimate directly, and the ratio of serum uric acid to creatinine has been studied in relation to estimated filtration rate in people with type 2 diabetes[11]. BUN adds information about hydration, protein turnover and kidney handling, and is particularly useful when a high urate value might simply reflect being dehydrated on the day of the draw. The link between urate and kidney injury risk is the reason these are grouped[5][6].
Then look at metabolic control. Fasting Glucose and Hemoglobin A1C describe short term and three month glucose exposure, and both tend to track with urate through insulin resistance. Routine blood markers cluster with metabolic hormones in population studies, which is part of why panels are read as a set rather than one line at a time[12].
Finally, inflammation. C-Reactive Protein rises during a gout flare and in many other states, and a broader Advanced Inflammation panel gives more context than a single inflammatory marker can. Antioxidant status is the other half of the picture, since urate is both a waste product and an antioxidant[2].
Uric acid tells you how well your body balances purine breakdown against renal clearance. Typical lab ranges sit around 2.5 to 7 mg/dL, FitScript's optimal targets are tighter, and the value is most informative when it is tracked over time next to kidney and metabolic markers. High results are usually silent and usually reflect reduced excretion. Low results are rarely flagged and are usually benign. Either way, the next step is the same, which is to discuss the result and any treatment with a clinician or licensed provider.
Most laboratories report a typical adult reference range of about 2.5 to 7 mg/dL. Ranges vary by lab, age and sex, so read your result against the range printed on your own report. FitScript's optimal range is 3.5 to 5.9 mg/dL for men and 2.5 to 5 mg/dL for women, which are optimization targets rather than diagnostic cut-offs.
The most common reason is reduced clearance by the kidneys rather than excess production. A clinician can work out which applies to you.
No. A raised level increases the likelihood that urate crystals can form, but many people with high values never develop gout, and some people with gout have values inside the reference range during a flare. Gout is a clinical diagnosis made by a clinician, sometimes supported by joint fluid analysis, not by a blood number alone.
Uric acid itself does not strictly require fasting, but it is usually drawn alongside markers that do, such as fasting glucose and lipids. Follow the instructions given with your draw. For comparable results over time, test under the same conditions each time, avoiding heavy alcohol, a large purine-rich meal and strenuous exercise the day before.
Low values are far less often flagged than high ones and usually cause no symptoms. They can reflect a low purine and low protein diet, medications or kidney tubule handling that increase urinary loss, reduced production in advanced liver disease, pregnancy, or rare inherited conditions. A very low result, or one alongside abnormal kidney or liver markers, is worth reviewing with a clinician.
The level responds to short term inputs such as hydration, alcohol, a single large purine-rich meal, fasting and intense exercise, so day to day variation is real. Sustained change usually follows sustained change in body composition, insulin sensitivity, kidney function or medication. That is why trends across repeat tests are more informative than any single value.
Kidney markers first, meaning eGFR, creatinine and BUN, because clearance drives most of the variation. Then metabolic markers such as fasting glucose and hemoglobin A1C, since urate tracks with insulin resistance. Inflammatory markers such as C-reactive protein add context, particularly around joint symptoms.
Diet is one lever and rarely the biggest one, because most circulating urate comes from your own cell turnover and most variation comes from kidney handling. Reducing alcohol and fructose-sweetened drinks, improving hydration and improving insulin sensitivity are associated with lower levels. Whether anything beyond lifestyle change is appropriate is a decision for a licensed provider who has reviewed your results.
Uric acid is measured on a routine blood chemistry draw and is one of the biomarkers in FitScript's testing, which covers 150+ biomarkers tested per year. Atlas, FitScript's AI health advisor, reads it next to kidney, glucose and inflammation markers rather than in isolation. Any prescription option is evaluated by a licensed provider.