Microscopic Haematuria Risk Interpreter (AUA/SUFU)
Microscopic Haematuria Risk Interpreter (AUA/SUFU)
Decide how far to investigate blood in the urine seen on microscopy. Enter age, sex, the red cell count per high-power field, smoking pack-years, any history of visible haematuria and other urothelial cancer risk factors, and the page assigns the AUA/SUFU low/negligible, intermediate or high risk stratum — on the current 2025 amendment or the 2020 original — with the recommended evaluation, and shows where UK referral practice differs.
Microhaematuria: what evaluation?
Age, sex, RBC/HPF, smoking, history → risk stratum and evaluationA 52-year-old woman, an ex-smoker with 5 pack-years, has 8 red cells per high-power field on microscopy of a clean-catch sample, no infection, no visible haematuria and no other risk factor.
AUA/SUFU risk strata
Low/negligible (all of): 3–10 RBC/HPF · woman under 60 (2020: under 50) or man under 40 · never or fewer than 10 pack-years · no other risk factor · no visible haematuria
Intermediate (any of): 11–25 RBC/HPF · man 40–59 · woman 60 or over (2020: 50–59) · 10–30 pack-years · other risk factor · persistent on repeat after low risk
High (any of): more than 25 RBC/HPF · visible haematuria · more than 30 pack-years · man 60 or over (2020: man or woman 60 or over)
- Pack-years
- packs a day × years smoked
- Risk factors
- irritative voiding symptoms, pelvic radiotherapy, cyclophosphamide or ifosfamide, family history of urothelial cancer or Lynch syndrome, benzene or aromatic amine exposure (AUA Table 3)
Worked example
A 52-year-old woman, an ex-smoker with 5 pack-years, has 8 red cells per high-power field on microscopy of a clean-catch sample, no infection, no visible haematuria and no other risk factor.
Microscopy, 8 RBC/HPF: 3 or more, so microhaematuria; no benign cause
High-risk criteria: no visible haematuria, 8 is not above 25, 5 pack-years is not above 30, and she is a woman → none met
Intermediate: 8 is not above 10, 5 pack-years is under 10, a woman under 60, no risk factor, first finding → none met
Low/negligible risk on the 2025 amendment: repeat urinalysis within 6 months. Under 2020 she would have been intermediate (a woman aged 50–59)
AUA/SUFU 2020 risk stratification, reconstructed (Table 4)
| Low risk — all of | Intermediate risk — any of | High risk — any of |
|---|---|---|
| Women under 50; men under 40 | Women 50–59; men 40–59 | Women or men 60 or over |
| Never smoker or under 10 pack-years | 10–30 pack-years | More than 30 pack-years |
| 3–10 RBC/HPF on a single urinalysis | 11–25 RBC/HPF | More than 25 RBC/HPF |
| No risk factors for urothelial cancer | Additional urothelial cancer risk factors | History of gross haematuria |
| Low-risk patient with no prior evaluation and 3–10 RBC/HPF on repeat urinalysis |
What the 2025 amendment changed, and where NICE differs
| AUA/SUFU 2020 | AUA/SUFU 2025 | NICE NG12 (UK) | |
|---|---|---|---|
| Women’s age | 50–59 intermediate; 60+ high | Under 60 low; 60+ intermediate; never high on age alone | — |
| Low risk | Shared decision: repeat UA or cystoscopy and ultrasound | Repeat UA within 6 months | — |
| Intermediate | Cystoscopy and renal ultrasound | Same; cytology or urine markers may be offered to guide cystoscopy | — |
| Urgent (2-week) referral | — | — | 45 or over with unexplained visible haematuria; 60 or over with unexplained non-visible haematuria and dysuria or a raised white cell count |
Why the dipstick is not the diagnosis
Microscopic haematuria — blood visible only under the microscope — is one of the commonest abnormal findings on a routine urinalysis, and most of it has no serious cause. The question the American Urological Association and the Society of Urodynamics, Female Pelvic Medicine and Urogenital Reconstruction set out to answer in 2020 was how to find the small number of bladder and kidney cancers without sending everyone for a CT scan. Their answer is a risk table. It starts with a definition: 3 or more red cells per high-power field on microscopy of a single, properly collected specimen, with no obvious benign cause. A positive dipstick is only a reason to look, because dipsticks also react to haemoglobin and myoglobin.
The table places a patient in the low (now low/negligible), intermediate or high stratum by age and sex, smoking pack-years, the red cell count, any history of visible haematuria and a short list of other risk factors. Low risk needs all of its criteria; intermediate and high need any one. The 2025 amendment kept the structure but moved women: a woman under 60 can now be low risk, and a woman is no longer high risk on age alone, because the validation studies found far lower cancer rates in women. It also turned the low-risk shared decision into a simple repeat urinalysis within six months, and allowed urine cytology or a validated urine tumour marker to guide cystoscopy in intermediate risk.
Two things the risk table does not do. It does not assess the kidney itself: protein, dysmorphic red cells, casts, hypertension or a raised creatinine call for a nephrology opinion alongside (see the urine protein-creatinine ratio calculator, the urine albumin-creatinine ratio calculator and the CKD-EPI 2021 eGFR calculator). And UK practice is built differently: NICE’s urgent-referral criteria turn on visible haematuria, and the older Renal Association and BAUS consensus accepts a dipstick of 1+ without microscopy. This interpreter supports, and does not replace, clinical judgement.
Frequently asked questions
How many red blood cells in urine is abnormal?
The AUA/SUFU guideline defines microhaematuria as 3 or more red blood cells per high-power field on microscopy of a single properly collected specimen, once obvious benign causes are excluded.
Is a positive urine dipstick for blood enough to diagnose microhaematuria?
Not on the AUA/SUFU guideline: a positive dipstick should prompt microscopy, because dipsticks also react to free haemoglobin and myoglobin. UK consensus guidance differs and accepts a dipstick of 1+ or more without microscopy.
What changed in the 2025 AUA microhematuria guideline?
Women under 60 can be low/negligible risk and women aged 60 or over are intermediate rather than high risk on age alone; low-risk patients have a repeat urinalysis within six months rather than a shared decision; and urine cytology or a validated tumour marker may be offered to guide cystoscopy in intermediate-risk patients.
What tests are done for high-risk microscopic haematuria?
Cystoscopy and axial imaging of the upper urinary tract, with multiphasic CT urography preferred where there is no contraindication. Intermediate risk gets cystoscopy and renal ultrasound.
Related calculators
References
- Barocas DA, Boorjian SA, Alvarez RD, et al. Microhematuria: AUA/SUFU guideline. J Urol. 2020;204(4):778–786. Statements 1, 2, 9–13; Tables 3 and 4.
- Barocas DA, et al. Updates to Microhematuria: AUA/SUFU Guideline (2025). J Urol. 2025. doi:10.1097/JU.0000000000004490. Risk strata as summarised in AUA News, July/August 2025 (AUA2025 plenary recap).
- National Institute for Health and Care Excellence. Suspected cancer: recognition and referral. NICE guideline NG12. 2015, updated; recommendations on bladder and renal cancer.
- Anderson J, Fawcett D, Feehally J, et al. Joint consensus statement on the initial assessment of haematuria. The Renal Association and British Association of Urological Surgeons; July 2008.
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.