Purpose:
Patients presenting with microhematuria represent a heterogeneous population with a broad spectrum of risk for genitourinary malignancy. Recognizing that patient-specific characteristics modify the risk of underlying malignant etiologies, this guideline sought to provide a personalized diagnostic testing strategy.
Materials and Methods:
The systematic review incorporated evidence published from January 2010 through February 2019, with an updated literature search to include studies published up to December 2019. Evidence-based statements were developed by the expert Panel, with statement type linked to evidence strength, level of certainty, and the Panel's judgment regarding the balance between benefits and risks/burdens.
Results:
Microhematuria should be defined as ≥ 3 red blood cells per high power field on microscopic evaluation of a single specimen. In patients diagnosed with gynecologic or non-malignant genitourinary sources of microhematuria, clinicians should repeat urinalysis following resolution of the gynecologic or non-malignant genitourinary cause. The Panel created a risk classification system for patients with microhematuria, stratified as low-, intermediate-, or high-risk for genitourinary malignancy. Risk groups were based on factors including age, sex, smoking and other urothelial cancer risk factors, degree and persistence of microhematuria, as well as prior gross hematuria. Diagnostic evaluation with cystoscopy and upper tract imaging was recommended according to patient risk and involving shared decision-making. Statements also inform follow-up after a negative microhematuria evaluation.
Conclusions:
Patients with microhematuria should be classified based on their risk of genitourinary malignancy and evaluated with a risk-based strategy. Future high-quality studies are required to improve the care of these patients.
Abbreviations and Acronyms
| CIS | carcinoma in situ |
| GRADE | Grading of Recommendations, Assessment, Development, and Evaluation |
| MH | microhematuria |
| RBC/HPF | red blood cells per high-power field |
| RCC | renal cell carcinoma |
| UA | urinalysis |
| UTUC | upper tract urothelial carcinoma |
Hematuria is one of the most common urologic diagnoses, estimated to account for over 20% of urology evaluations.1 Indeed, screening studies have noted a prevalence range of microhematuria (MH) among healthy volunteers of 2.4%-31.1% depending on the specific population evaluated.2
The differential diagnosis of MH encompasses a wide range of urologic, nephrologic, as well as gynecologic conditions. Importantly, while genitourinary malignancy has been diagnosed in approximately 3% of patients evaluated for MH,2,3 the risk of detecting an underlying cancer has been found to be highly dependent on factors such as sex, age, smoking history, and degree of hematuria.4
As the aggregate likelihood of identifying a malignancy among patients with MH is relatively low, the benefits and potential harms of diagnostic evaluation must be considered both at the patient and health system level.
At the same time, practice-pattern assessments have demonstrated significant deficiencies in the evaluation of patients presenting with hematuria. For example, one study found that less than 50% of patients with hematuria diagnosed in a primary care setting were subsequently referred for urologic evaluation.5 Furthermore, performance of both cystoscopy and imaging occurs in less than 20% of patients in most series, and varies to some degree by sex and race.6–8 The underuse of cystoscopy, and the tendency to rely solely on imaging for evaluation, is particularly concerning since the vast majority of cancers diagnosed among persons with hematuria are bladder cancers, optimally detected with cystoscopy.4,6–14
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