Discriminative capacity of guideline recommendations in the assessment of patients with asymptomatic microhematuria

•Asymptomatic microhematuria is a frequent condition and triggers invasive workup.•Current guideline recommendations lack sufficient discriminatory capacity to spare patients from unnecessary interventions.•Development and validation of a nomogram, potentially including urine markers, is recommended. Asymptomatic microhematuria (aMh) remains a diagnostic challenge in urological practice: while aMh is a risk factor of urothelial carcinoma (UC), prevalence of aMh is high. Guidelines were developed to permit risk stratification and reduce diagnostic workload. This study investigates the efficacy of several recommendations. Sixty hundred eight patients with newly diagnosed aMh without previous UC from an academic referral center (A; n = 320) and a private outpatient clinic (B; n = 288) were included. All patients underwent clinical workup including medical history, urine cytology, upper tract imaging and cystoscopy. Eleven former and current guidelines were applied to each patient individually; every patient was classified as either low risk (no further workup recommended) or high risk. Furthermore, a recently developed nomogram for hematuria assessment was included. The cohort comprised 142 females and 466 males (mean age 62 [range 18–92] years). Sixty-one patients (10.0%) were diagnosed with UC. Excluding the Swedish and recent NICE guideline generally advising against urologic workup, application of 9 other recommendations would have diagnosed all UCs and saved 1.6% to 16.1% of patients from workup. For the 2020 US guideline, solely applied to cohort B, 10.6% of patients were classified as low risk. The use of the nomogram would have saved 17.1% to 25% of patients from workup. Practical relevance of current guidelines is limited as they do not sufficiently identify patients not requiring clinical work up. Thus, guideline adherence may trigger overdiagnosis and even overtreatment. New ways of risk stratification are needed to improve aMh assessment.