Asymptomatic Microscopic Hematuria. What is the Best Approach?

Abstract

Introduction: Asymptomatic microscopic hematuria (AMH) is commonly found in Primary Health Care (PHC).The importance of this finding is secondary to the potential underlying risk of clinically significant pathology, including malignancy, urolithiasis and medical kidney disease.

While macroscopic hematuria is recognized as a sign that should lead to urological referral for evaluation, the recommended investigation of microscopic and, in particular, asymptomatic hematuria is inconsistent among the available guidelines.

Our objective was to review the main guidelines on the assess- ment and approach of AMH and to provide an approach algorithm

Methods: Bibliographic search of scientific articles in the PubMed, UpToDate and Cochrane Library databases, published in the last 5 years, using the combination of MeSH terms “Hematuria / diagnosis”, in English and Portuguese. Consultation of the guidelines of the American Urology Association (AUA) and the Portuguese Urology Association.

Results: A total of 733 research articles were obtained. Five review articles were selected, due to their adequacy to the main objective. The 2020 systematic review, which includes the most recent AUA guidelines, shows that careful history and physical examination are recommended by all revised guidelines, allowing to identify potential benign etiologies that, if confirmed, may avoid the need to proceed with an assessment additional.

In addition to urinary sediment, the determination of renal function is recommended in the exclusion of renal pathology. There is con- sensus by the guidelines that cystoscopy should be performed. Regarding radiological evaluation, the most current guideline is based on stratifying the risk of malignancy when requesting additional tests.

Discussion: Current guidelines differ on important details such as the definition of AMH, the ideal method for radiological evaluation and the role of urine cytology. It is important to note that these variations reflect the absence of level I evidence on the subject.