From the Guidelines
Finding 7 red blood cells (RBCs) per high power field (HPF) in urine is considered mildly elevated and suggests microscopic hematuria. Normal urine typically contains 0-3 RBCs per HPF, so a value of 7 RBCs/HPF indicates a small amount of blood in the urine that isn't visible to the naked eye. This finding warrants further evaluation to determine the underlying cause, though it may not represent a serious condition. Potential causes include:
- Urinary tract infection
- Kidney stones
- Glomerular disease
- Medication effects
- Strenuous exercise
- Trauma to the urinary tract In some cases, contamination during sample collection (especially in menstruating women) can produce this result. Follow-up testing is recommended, including urinalysis with microscopy, urine culture if infection is suspected, and possibly imaging studies like ultrasound or CT scan depending on associated symptoms and clinical context. Patients should increase fluid intake to help flush the urinary system and report any symptoms like pain, burning during urination, or visible blood in urine. The significance of this finding depends on other clinical factors, patient history, and whether it persists on repeat testing, as suggested by the American College of Physicians 1. It is essential to consider the patient's risk factors for significant disease, such as age, sex, and medical history, when deciding on the extent of evaluation, as recommended by the American Urological Association 1. Given the potential for underlying conditions, further evaluation is necessary to determine the cause of microscopic hematuria, and patients should be managed based on their individual risk factors and clinical presentation, as advised by the American College of Physicians 1.
From the Research
Hematuria Evaluation
- Hematuria is a condition characterized by the presence of red blood cells in the urine, which can be either microscopic or gross.
- The evaluation of hematuria involves various tests, including urinalysis, imaging studies, and cystoscopy.
Red Blood Cells per High Power Field (RBCs/HPF)
- The presence of 7 RBCs/HPF in the urine may indicate hematuria, but the clinical significance of this finding depends on various factors, including the patient's symptoms, medical history, and other laboratory results.
- According to the study by 2, referral to urology is recommended for patients with asymptomatic microscopic hematuria or symptomatic hematuria that produces >3 RBCs/HPF on two of three properly performed and collected urinalyses.
- The study by 3 suggests that patients with <5 RBCs/HPF on three urinalyses are unlikely to have significant pathology and could possibly be followed up conservatively.
Diagnostic Approach
- The diagnostic approach to hematuria involves a combination of laboratory tests, imaging studies, and cystoscopy.
- The study by 4 recommends that patients with hematuria undergo imaging studies, such as computed tomography urography, to evaluate the upper tracts.
- The study by 5 suggests that dipstick evaluation of hematuria can be used as a screening test, but microscopic examination is necessary to confirm the diagnosis and predict the need for further testing.
Clinical Significance
- The presence of 7 RBCs/HPF in the urine may indicate a underlying urological condition, such as a urinary tract infection, kidney stones, or bladder cancer.
- However, the study by 6 suggests that asymptomatic microscopic hematuria may not always require a full urological investigation, and that the decision to investigate should be based on individual patient factors, such as medical history and other laboratory results.