Uric acid: what it is, what it tells you and why we test it
Uric acid is what is left when your body breaks down purines, substances found in your own cells and in some foods. Your kidneys clear most of it. It is less a problem to fix than a sign of how your metabolism is doing.
Why we test it
When uric acid stays high for a long time, it can form tiny crystals. In the joints they cause gout, in the kidneys stones.
It also matters as a signal. It often rises together with weight, blood pressure, triglycerides and glucose, so it shows how your metabolism is doing.
It can stay high for years without symptoms. A blood test picks it up earlier.
What it tells you, and what it does not
If it is high, the risk of gout and kidney stones goes up, most of all when it is very high. But most people with high uric acid do not develop gout.
It often comes down to habits and weight: alcohol, sugary drinks, a few extra kilos. Sometimes the kidneys or a medicine are involved.
Lowering it has not been shown to protect the heart. That is why it matters to understand why it rises.
That is why it is read together with other tests:
- Creatinine: Whether your kidneys clear it well
- eGFR: How well your kidneys filter, for your age
- Glucose: Whether your blood sugar is high too
- Triglycerides: Whether the fats in your blood are high too
Normal uric acid levels
The lab decides what is normal. It is usually 2.4 to 5.7 mg/dL for women and 3.4 to 7 for men. Your own report may print different limits.
Men usually have higher levels. In women, female hormones help the kidneys clear it, so after menopause the level tends to rise.
Your report may also call it serum urate, or uricemia on an Italian report: it is the same test.
In the Rosa report you also see your optimal range and what to do to reach it or stay in it.
What your result means
Find the row for your result, in mg/dL. At 9 or above it should always be seen by a doctor, even if you have no symptoms.
- Below your report’s limit, Women: usually below 2.4, Men: usually below 3.4: Low. It is usually not a problem, and there is nothing to do. If it is below 2, talk to a doctor, especially if you train hard or have had kidney stones.
- Within your report’s limits, Women: usually 2.4 to 5.7, Men: usually 3.4 to 7: Normal. Usually fine. Read it together with your glucose, triglycerides and weight. In the Rosa report you also see whether you are in your optimal range.
- Above your report’s limit, below 9, Women: usually above 5.7, Men: usually above 7: High. It can come from alcohol, sugary drinks, weight, some medicines or kidneys that filter less. Read it with creatinine and eGFR. Without symptoms, you usually start with alcohol, sugary drinks and weight.
- 9 and above: Very high. The risk of gout and kidney stones is higher. Talk to a doctor, even if you have no symptoms.
If your uric acid is high or low
- High uric acid: Alcohol, sugary drinks or a few extra kilos are often behind it. It usually causes no symptoms.
- Low uric acid: It is usually not a problem. Below 2 mg/dL, talk to a doctor.
What can skew the result
A few things push it up for a while. It helps to know them before you read it.
- Alcohol: Beer and spirits most of all. Even a night of drinking in the days before can raise it.
- Red meat, organ meats and shellfish: They are rich in purines. Many such meals in the days before can raise it a little.
- Fasting and crash diets: Going without food for several days, or losing weight very fast, raises it for a while. The overnight fast before the blood test is fine.
- Hard exercise: A very tough workout the day before can raise it. Arrive at the blood test rested.
When to worry
Talk to a doctor if:
- Your uric acid is 9 or above.
- You have had gout attacks or kidney stones.
- It is high and your eGFR is low too.
- It is below 2, especially if you train hard or have had kidney stones.
- A joint is swollen, red and very painful: get seen the same day, straight away if you also have a fever.
With Rosa, a uric acid of 9 or above is always flagged to a doctor.
Frequently asked questions
What are normal uric acid levels? The lab decides: usually 2.4 to 5.7 mg/dL for women and 3.4 to 7 for men. The limit printed on your own report is the one that counts.
Why is it higher in men than in women? Female hormones help the kidneys clear it. That is why women have lower levels, and after menopause their levels move closer to men’s.
Do I need to fast for a uric acid test? Usually yes, also because it is done with other tests that need fasting. The day before, avoid alcohol and very hard workouts. You can drink water.
How often should it be checked? For people who feel well there is no fixed rule: Rosa measures it once a year. If it is out of range, it is usually checked again after about three months, or sooner if your doctor says so.
Low uric acid: what does it mean? Usually nothing: above 2 mg/dL a low level is not a problem, and some medicines lower it as an expected effect. Below 2 is rare, and it can mean your kidneys lose too much of it. Talk to a doctor, especially if you train hard or have had kidney stones.
Can I test my uric acid myself? There are meters that read a drop of blood from your finger, like the ones for blood sugar. They can help people who need to check it often, on their doctor’s advice. For a proper check-up you need a blood draw at a lab, read together with your other tests.
Sources
- American College of Rheumatology, guideline for the management of gout. Arthritis Care & Research, 2020. PMID 32391934
- Dalbeth and colleagues, serum urate and the risk of gout in four large population cohorts. Annals of the Rheumatic Diseases, 2018. PMID 29463518
- Choi and colleagues, purine-rich foods, dairy and protein intake and the risk of gout. New England Journal of Medicine, 2004. PMID 15014182
- Choi and colleagues, alcohol intake and the risk of gout: beer, spirits and wine compared. The Lancet, 2004. PMID 15094272
- Mazzierli and colleagues, very low uric acid from a kidney transport defect, and kidney injury after exercise. Journal of Nephrology, 2023. PMID 36418779
