When to repeat urinalysis in a patient with microscopic hematuria (microscopic blood in urine)?

From the Guidelines

Repeat urinalysis should be performed after the resolution of the gynecologic or non-malignant genitourinary cause of microhematuria, as recommended by the American Urological Association (AUA) guideline 1. When to repeat urine with microhematuria again is a crucial decision that depends on various factors, including the underlying cause of the microhematuria and the presence of risk factors for urologic malignancy.

Key Considerations

• The AUA guideline defines microhematuria as 3 red blood cells per high power field on microscopic evaluation of a single specimen 1.
• Patients diagnosed with gynecologic or non-malignant genitourinary sources of microhematuria should undergo repeat urinalysis following resolution of the underlying cause 1.
• The timing of repeat testing is important, as transient microscopic hematuria can occur due to various factors such as exercise, menstruation, sexual activity, or minor infections, while persistent hematuria may indicate underlying urologic conditions requiring investigation.

Risk Factors and Evaluation

• Certain situations may require more urgent repeat testing, such as in patients with risk factors for urologic malignancy (smoking history, age over 50, occupational exposures), those with symptoms like flank pain or dysuria, or patients on anticoagulation therapy 1.
• A thorough history, physical examination, urinalysis, and serologic testing should be performed prior to any initial imaging 1.
• Ultrasound, CT, and MRI are the most common imaging modalities used to evaluate hematuria, and the choice of imaging modality depends on the clinical scenario and the presence of risk factors 1.

From the Research

Evaluation of Microscopic Hematuria

• The presence of three or more red blood cells per high-power field in a properly collected urine specimen without evidence of infection is defined as asymptomatic microscopic hematuria 2.
• Microscopic hematuria can be caused by various factors, including urinary tract infection, benign prostatic hyperplasia, and urinary calculi, but up to 5% of patients may have a urinary tract malignancy 2.

Follow-up Evaluation

• If microscopic hematuria persists after treatment of a urinary tract infection, a diagnostic workup is warranted 2, 3.
• Patients with persistent microhematuria after 3 months without a definitive diagnosis may benefit from further evaluation, such as intravenous urography (IVU) 4.
• The American Urological Association recommends a diagnostic workup for patients with asymptomatic microscopic hematuria, including evaluation of the upper and lower urinary tracts 2.

Timing of Repeat Urine Test

• A repeat urine test may be necessary after 3 months if microhematuria persists without a definitive diagnosis 4.
• Patients with resolution of microhematuria may not require further evaluation, but those with persistent microhematuria should undergo further testing to determine the underlying cause 4.