Ery/ul stands for erythrocytes per microliter, which is a measurement of the number of red blood cells (RBCs) found in a sample of urine. The presence of these cells is medically termed hematuria, which indicates bleeding somewhere along the urinary tract, from the kidneys to the urethra. A result of 50 ery/ul is significantly above the typical reference range, confirming the presence of blood cells that require further medical attention. This finding classifies as microscopic hematuria, meaning the blood is not visible to the naked eye but is detectable only under a microscope. While a single test result is not a diagnosis, this level of red blood cells prompts a full medical evaluation to determine the underlying cause.
Understanding the Urinalysis Result
A urinalysis report uses the ery/ul measurement to quantify the presence of red blood cells in the urine sediment. In most healthy individuals, the count is very low, with a generally accepted normal range being between zero and five erythrocytes per high-power field (HPF). The reported value of 50 ery/ul is approximately ten times the upper limit of this normal range, making it a clear indicator of microscopic hematuria.
Microscopic hematuria is distinct from gross, or macroscopic, hematuria, where the amount of blood is large enough to visibly change the color of the urine to pink, red, or cola-colored. The amount of blood corresponding to 50 ery/ul is only detectable by laboratory analysis, not by visual inspection. The main purpose of identifying this microscopic level is to alert a healthcare provider to a potential underlying issue.
Common and Temporary Explanations
The most frequent reasons for a transient elevation in urinary red blood cells are often benign and temporary. Strenuous physical activity, sometimes referred to as “runner’s hematuria,” can cause a temporary rise in the erythrocyte count. This can be due to mechanical trauma, such as the repeated impact of the bladder wall during intense exercise, particularly when the bladder is empty. Furthermore, the body’s response to intense exercise involves renal vasoconstriction, which may lead to brief hypoxic damage.
Recent sexual activity is another common and temporary cause, especially in women, due to minor localized trauma to the trigone region of the bladder or the urethra. This minor irritation can cause a small, transient bleed that is captured in the subsequent urine sample. Mild dehydration also contributes indirectly by concentrating the urine, which can irritate the lining of the urinary tract and increase the risk of crystallization or infection.
Urinary tract infections (UTIs) are also highly common causes, as the inflammation caused by bacterial infection irritates the mucosal lining of the bladder and urethra. Once a UTI is treated with appropriate antibiotics, the hematuria typically resolves completely. In women, menstrual contamination is a simple, non-pathological reason for a positive test, which can be ruled out by collecting a clean-catch sample after the menstrual cycle has ended.
Conditions Requiring Further Medical Investigation
When temporary causes like infection or exercise are ruled out, the persistent presence of 50 ery/ul requires investigation for more chronic conditions affecting the urinary system.
Kidney stones cause bleeding through physical trauma as they move or pass down the ureters. These sharp, crystallized masses scrape and irritate the delicate tissue lining the urinary tract, causing the release of red blood cells. Even small, non-obstructing stones can cause microscopic bleeding.
Conditions affecting the kidney’s filtering units, known as glomerulonephritis, are another serious consideration. This involves immune-mediated inflammation or damage to the glomeruli, which are responsible for filtering blood. When the glomerular basement membrane is compromised, it allows red blood cells to leak through the damaged barrier and into the urine. Red blood cells originating from this type of damage often appear misshapen, or dysmorphic, when viewed under a microscope.
In rare cases, persistent microscopic hematuria can be an early indicator of a tumor within the urinary tract, such as bladder or kidney cancer. These masses often develop fragile, excessive blood vessels that can bleed easily, leading to the presence of red blood cells in the urine. While malignancy is a concern that must be excluded, it is important to remember that it is a less common cause than many of the benign conditions.
The Diagnostic Process and Follow-Up
The first step in a medical evaluation is usually to repeat the urinalysis to confirm that the hematuria is persistent and not transient. If the result remains elevated, the diagnostic process proceeds in a logical sequence to pinpoint the bleeding source. Blood tests are performed to assess overall kidney function, specifically checking levels of creatinine and the estimated glomerular filtration rate.
Imaging studies are typically ordered to visualize the internal structures of the urinary tract. A renal ultrasound or a Computed Tomography (CT) Urogram is often used to examine the kidneys for masses, cysts, or the presence of kidney stones. The CT Urogram, in particular, uses a contrast dye to provide detailed images of the entire upper urinary tract, including the kidneys and ureters.
For a persistent finding of 50 ery/ul, especially in individuals with risk factors like a history of smoking or age over 40, a procedure called cystoscopy may be performed. A urologist uses this thin, lighted instrument to directly examine the lining of the bladder and urethra for any visible lesions or sources of bleeding. The combination of laboratory data and imaging allows the healthcare provider to determine the cause and recommend the most appropriate management plan.