From the Guidelines
A patient with microscopic hematuria should be referred to the Emergency Room when accompanied by signs of acute illness or concerning symptoms, such as severe flank or abdominal pain, fever, signs of urinary obstruction, acute kidney injury, significant uncontrolled bleeding, hypotension, tachycardia, or altered mental status, as these conditions can significantly impact morbidity, mortality, and quality of life. Patients with microscopic hematuria who have experienced recent trauma, particularly to the abdomen or pelvis, should also seek immediate care 1. Additionally, immediate evaluation is warranted if the patient has symptoms of a urologic emergency such as priapism, testicular torsion, or Fournier's gangrene. Most cases of isolated microscopic hematuria without these concerning features can be evaluated in an outpatient setting with urinalysis, imaging studies, and possible referral to urology. The urgency of evaluation depends on the clinical context, as microscopic hematuria can range from benign causes like vigorous exercise to serious conditions like malignancy or glomerulonephritis. The presence of red cell casts or significant proteinuria alongside microscopic hematuria suggests glomerular disease and may require prompt nephrology consultation, though not necessarily emergency care unless accompanied by acute kidney injury or other concerning symptoms.
Some key considerations for referral include:
- Severe symptoms such as severe flank or abdominal pain, fever, or signs of urinary obstruction
- Recent trauma, particularly to the abdomen or pelvis
- Symptoms of a urologic emergency
- Presence of red cell casts or significant proteinuria alongside microscopic hematuria
- Acute kidney injury or other concerning symptoms
It is essential to prioritize the evaluation and management of patients with microscopic hematuria based on their individual clinical context and risk factors, as outlined in the most recent guidelines and evidence-based recommendations 1.
From the Research
Referral to the Emergency Room (ER)
When considering referral to the ER for a patient with microscopic hematuria, several factors must be taken into account.
- The presence of microscopic hematuria, defined as three or more red blood cells per high-power field in a properly collected urine specimen, may indicate a benign condition such as urinary tract infection, benign prostatic hyperplasia, or urinary calculi 2.
- However, up to 5% of patients with asymptomatic microscopic hematuria may have a urinary tract malignancy, highlighting the importance of a thorough evaluation 3.
- Patients with risk factors for malignancy, such as age greater than 35 years, male sex, or a history of smoking, should be referred for further evaluation 3.
- The American Urological Association recommends urologic evaluation for patients with both microscopic and gross hematuria, but primary care physicians may not always refer patients with microscopic hematuria to urology 4.
Indications for ER Referral
The following indications may warrant referral to the ER:
- Gross hematuria, which has a higher risk of malignancy than microscopic hematuria 2, 5.
- Severe symptoms such as severe pain, difficulty urinating, or signs of infection 5.
- Patients with a history of smoking or environmental exposure, who are at higher risk for bladder cancer 6.
- Patients with dysmorphic red blood cells, cellular casts, proteinuria, elevated creatinine levels, or hypertension, which may indicate underlying renal disease 3.
Evaluation and Management
Patients with microscopic hematuria should undergo a thorough evaluation, including:
- Urinalysis to confirm the presence of hematuria and rule out infection 2, 3.
- Imaging studies such as multiphasic computed tomography urography to evaluate the upper urinary tract 3.
- Cystoscopy to evaluate the lower urinary tract 3.
- Referral to nephrology and urology subspecialists if no benign cause is found or if there are risk factors for malignancy 2, 3.