Serum Urate Target in Gout: Below 6 or 5 mg/dL? Interpreter
Serum Urate Target in Gout: Below 6 or 5 mg/dL? Interpreter
Check a serum urate (uric acid) against the treat-to-target goals for gout: below 6 mg/dL (360 µmol/L) in the ACR 2020 and EULAR 2016 guidelines, and below 5 mg/dL (300 µmol/L) for severe or tophaceous gout in EULAR’s. Enter the result in mg/dL, µmol/L or mmol/L; the page gives the value in both units, where it sits against each target and the saturation point, and why a normal urate during a flare does not exclude gout.
Is the urate at the gout target?
Urate, unit, gout severity → treat-to-target verdictA 58-year-old man with gout, on allopurinol 200 mg daily, has a serum urate of 7.4 mg/dL. He has no tophi and one flare in the last year.
Targets and the saturation point
Target, all patients with gout: below 6 mg/dL (ACR 2020; EULAR 2016, printed as 360 µmol/L)
Target, severe gout — tophi, chronic arthropathy, frequent flares: below 5 mg/dL (EULAR, printed as 300 µmol/L)
Not below 3 mg/dL long term (EULAR). Hyperuricaemia: 6.8 mg/dL or more (ACR 2020 definition)
- 59.4849
- 10,000 ÷ 168.11, the molar mass of uric acid — the factor the uric acid unit converter uses
- 6.8 mg/dL
- the ACR definition of hyperuricaemia, close to the concentration at which urate saturates plasma at body temperature
- treat to target
- titrating urate-lowering therapy until the urate is below the target, then keeping it there
Worked example
A 58-year-old man with gout, on allopurinol 200 mg daily, has a serum urate of 7.4 mg/dL. He has no tophi and one flare in the last year.
7.4 mg/dL × 59.4849 = 440 µmol/L
Not below 6 mg/dL → not at the ACR or EULAR target
6.8 mg/dL or more → hyperuricaemia by the ACR definition: crystals can still form
Titrate the allopurinol dose and recheck; add flare prophylaxis while titrating
Urate targets in gout guidelines
| Guideline | All patients on urate-lowering therapy | Severe gout |
|---|---|---|
| ACR 2020 | Below 6 mg/dL | Below 6 mg/dL — no trial data for a lower target |
| EULAR 2016 | Below 6 mg/dL (360 µmol/L) | Below 5 mg/dL (300 µmol/L) |
| NICE NG219, 2022 | Below 360 µmol/L | Consider below 300 µmol/L |
| BSR 2017 | Below 300 µmol/L | Below 300 µmol/L |
A target for treatment, not a test for gout
Gout is caused by monosodium urate crystals, which form when urate in the blood is above its saturation point — close to 6.8 mg/dL at body temperature, the level the ACR uses to define hyperuricaemia — and dissolve when it is brought below it. That is the logic of treat-to-target: urate-lowering therapy is titrated until the serum urate is below a target set comfortably under the saturation point, and kept there. The 2020 American College of Rheumatology guideline and the 2016 EULAR recommendations both set the target below 6 mg/dL. EULAR adds a lower target, below 5 mg/dL, for severe gout — tophi, chronic arthropathy or frequent attacks — to dissolve crystals faster; the ACR declines to, finding no trial data for a lower target. EULAR also advises against a urate below 3 mg/dL in the long term. In the UK the BSR sets 300 µmol/L for everyone and NICE 360 µmol/L, with 300 to be considered for severe disease. The uric acid unit converter converts units with the same factor this page uses.
The urate is a treatment target, not a diagnostic test. Most people with a raised urate never have gout, and the ACR guideline advises against treating asymptomatic hyperuricaemia. Conversely, urate falls during an acute attack and returns to its usual level afterwards, so a normal value taken during a flare does not exclude gout: a recent review found normal urate during attacks in between 11% and 63% of patients across studies. Gout is diagnosed by finding urate crystals in joint fluid (see the synovial fluid crystal interpreter), and the urate should be rechecked a few weeks after the flare.
Two small traps catch people moving between units. EULAR prints its targets as 6 mg/dL “(360 µmol/L)” and 5 mg/dL “(300 µmol/L)”, but at the exact conversion 6 mg/dL is 357 µmol/L and 5 mg/dL is 297 µmol/L, so a value of 358 µmol/L meets one figure and not the other. And mmol/L results (0.36 rather than 360) are easy to misread by a factor of 1000. For the kidney’s handling of urate, see the fractional excretion of uric acid calculator. This page supports, and does not replace, clinical judgement.
Frequently asked questions
What should uric acid be in gout?
Below 6 mg/dL (about 360 µmol/L) for most people on urate-lowering therapy, according to the ACR 2020 and EULAR 2016 guidelines. EULAR sets below 5 mg/dL (about 300 µmol/L) for tophi, chronic arthropathy or frequent flares, which the ACR does not; the BSR uses 300 µmol/L for everyone.
Can uric acid be normal during a gout attack?
Yes. Urate often falls during a flare and returns to its usual level afterwards; studies have found normal urate during attacks in about a third to over 40% of patients. Recheck a few weeks after the flare, and confirm gout with joint fluid crystals.
What is the saturation point of uric acid?
Close to 6.8 mg/dL (about 400 µmol/L) at body temperature, the level the ACR uses to define hyperuricaemia. Above it urate can crystallise; below it crystals slowly dissolve, which is why targets are set below 6 or 5 mg/dL.
Can uric acid be too low on treatment?
EULAR advises against keeping urate below 3 mg/dL in the long term. Once tophi have gone, the dose can usually be reduced to keep the urate below 6 mg/dL.
Related calculators
References
- FitzGerald JD, Dalbeth N, Mikuls T, et al. 2020 American College of Rheumatology guideline for the management of gout. Arthritis Rheumatol. 2020;72(6):879–895. Also published in Arthritis Care Res. 2020;72(6):744–760.
- Richette P, Doherty M, Pascual E, et al. 2016 updated EULAR evidence-based recommendations for the management of gout. Ann Rheum Dis. 2017;76(1):29–42.
- National Institute for Health and Care Excellence. Gout: diagnosis and management. NICE guideline NG219. June 2022.
- Hui M, Carr A, Cameron S, et al. The British Society for Rheumatology guideline for the management of gout. Rheumatology. 2017;56(7):e1–e20.
- Normal serum uric acid gout: a neglected and challenging condition. Front Endocrinol. 2026. doi:10.3389/fendo.2026.1873856.
- Logan JA, Morrison E, McGill PE. Serum uric acid in acute gout. Ann Rheum Dis. 1997;56(11):696–697.
Medical Disclaimer: The tools and content provided here are for educational and reference purposes only. They are not intended to substitute for professional medical advice, diagnosis, or treatment. Clinical decisions should always be based on the comprehensive assessment of a qualified healthcare professional.