A finding of 70 leukocytes in a urine test signals that the body’s immune system is actively responding to a disturbance within the urinary tract. Leukocytes, or white blood cells, function as primary defenders against foreign invaders and injury. Their presence in the urine indicates pyuria, a clear sign of inflammation or infection somewhere along the urinary system. While this result strongly suggests a problem, the urinalysis alone does not identify the specific cause. The result of 70 is substantially elevated and necessitates follow-up to determine the underlying source of the immune response.
Understanding Leukocytes and the Urinalysis
Leukocytes are immune cells produced in the bone marrow that circulate through the blood and tissues to patrol for pathogens, such as bacteria, viruses, or fungi. When an infection or injury occurs in the urinary system, these cells migrate to the site of irritation to neutralize the threat. The presence of these white blood cells in the urine is referred to as pyuria.
A standard urinalysis uses two main methods to detect these cells. The first is a chemical dipstick test, which detects the enzyme leukocyte esterase released by certain types of leukocytes. The second, and more precise, method is a microscopic examination, where a small sample of concentrated urine is viewed under a microscope to count the actual number of white blood cells present. This microscopic count provides the quantitative number, such as the finding of 70.
Interpreting an Elevated Leukocyte Count
The normal range for leukocytes in a microscopic urinalysis is extremely low, typically considered to be 0 to 5 white blood cells per high-power field (WBCs/hpf). A count above 10 WBCs/hpf is generally accepted as meeting the definition of pyuria, indicating an abnormal level of inflammation. Therefore, a result of 70 is an extremely high count, confirming a robust immune response is underway.
This elevated number translates directly to a medical need for prompt investigation to identify the origin of the inflammation. The high count suggests that the body is battling a significant irritant or a substantial infection somewhere in the urinary system. The raw number 70 itself is not a diagnosis, but rather a measurement of the severity of the inflammatory reaction.
Primary Causes of Elevated Urine Leukocytes
The most frequent cause behind such a dramatically elevated leukocyte count is a bacterial urinary tract infection (UTI). This occurs when bacteria, often Escherichia coli from the bowel, colonize the urethra and bladder. The high number of white blood cells is the immune system’s direct attempt to eliminate the invading bacteria. The presence of both leukocytes and bacteria in the urine sediment strongly points toward an active bacterial infection.
When a high leukocyte count is accompanied by symptoms like fever, flank pain, or nausea, the infection may have progressed to the kidneys, a serious condition known as pyelonephritis. Pyelonephritis is a more severe form of UTI where the bacteria have traveled up the ureters into the renal tissue, causing intense inflammation. This migration of infection requires more aggressive treatment to preserve kidney function.
Other mechanical causes, such as the presence of kidney stones, can also trigger a high leukocyte count. A stone obstructing the flow of urine or causing chronic irritation to the lining of the urinary tract can provoke a severe inflammatory reaction. Even without a simultaneous bacterial infection, the physical trauma and obstruction caused by the stone can lead to a significant elevation in white blood cells.
A high leukocyte count without detectable bacteria in a standard culture is referred to as sterile pyuria. This condition can be caused by infections from organisms that are difficult to culture, such as Chlamydia trachomatis or certain viruses. Sterile pyuria may also be a sign of non-infectious inflammatory conditions, including interstitial nephritis (inflammation of the kidney tubules), or a side effect of certain medications.
Follow-up Diagnostic Steps and Treatment
To move from the finding of 70 leukocytes to a definitive diagnosis, the immediate next step is typically a urine culture. This test involves placing the urine sample in a medium to allow any potential bacteria to multiply and grow, which confirms the presence of an infection and identifies the specific bacterial species responsible. Identifying the bacteria is critical because it allows for the determination of which antibiotic will be most effective.
If the initial culture is negative despite the high leukocyte count, further diagnostic tests may be necessary. Blood work can assess kidney function and detect signs of a systemic infection, such as sepsis. Imaging studies, including an ultrasound or CT scan, are often ordered when kidney stones, anatomical abnormalities, or an obstruction are suspected as the cause of the inflammation.
Treatment is always directly tied to the underlying cause identified by the diagnostic process. For a confirmed bacterial infection, a course of antibiotics is prescribed, specifically chosen based on the results of the urine culture sensitivity testing. Infections that have reached the kidney, like pyelonephritis, may require intravenous antibiotics in a hospital setting to ensure the infection is fully eradicated. If a kidney stone is the cause, treatment will focus on pain management, encouraging the stone to pass, or procedures to remove larger stones.