White blood cells are an integral part of the body’s immune system. Their presence in urine often signals an underlying health issue within the urinary tract or elsewhere in the body, indicating an active immune response.
Detecting White Blood Cells in Urine
The detection of white blood cells in urine typically occurs through a laboratory test called urinalysis. A common initial screening method is the urine dipstick test, which checks for leukocyte esterase, an enzyme found in certain white blood cells. A positive result suggests inflammation or infection.
Following a positive dipstick result, a microscopic examination of the urine sediment provides a more precise count of white blood cells. The medical term for the presence of white blood cells or pus in urine is pyuria. While a small number of white blood cells (typically 0 to 5 cells per high power field) can be normal, an elevated count indicates an abnormal condition.
Underlying Reasons for Elevated White Blood Cells
The most frequent cause of white blood cells appearing in urine is a urinary tract infection (UTI). UTIs can affect any part of the urinary system, including the urethra, bladder, and kidneys.
Infections that ascend to the kidneys, known as pyelonephritis, are a more severe form of UTI. Inflammation confined to the bladder, or cystitis, also frequently causes white blood cells to appear in urine. Blockages in the urinary tract, such as those caused by kidney stones, can disrupt urine flow and create an environment conducive to infection, leading to pyuria.
Certain sexually transmitted infections (STIs), including chlamydia and gonorrhea, can cause white blood cells to be present in the urine, sometimes even without bacteria detectable by standard cultures, a condition termed sterile pyuria. In men, inflammation of the prostate gland, or prostatitis, can lead to an increased number of white blood cells in urine. Beyond infections, some medications, such as nonsteroidal anti-inflammatory drugs (NSAIDs), certain antibiotics, and proton pump inhibitors, can contribute to pyuria.
Systemic inflammatory conditions, like lupus or Kawasaki disease, can cause white blood cells in the urine. The presence of white blood cells can also be due to contamination of the urine sample during collection, especially from vaginal secretions. Other less common reasons include tumors in the urinary tract or physiological changes such as those occurring during pregnancy.
Accompanying Symptoms and Diagnostic Process
The presence of white blood cells in urine is often accompanied by a range of symptoms. Individuals might experience painful urination, a frequent urge to urinate, or a feeling of urgency. The urine itself may appear cloudy, have a foul odor, or, in some cases, contain visible blood.
More generalized symptoms can include lower abdominal pain or discomfort, and if the infection has spread to the kidneys, fever, chills, and back or flank pain may develop. To determine the specific cause of elevated white blood cells, a healthcare provider will often order additional tests. A urine culture and sensitivity test is commonly performed to identify the type of bacteria present and determine which antibiotics will be most effective for treatment.
If kidney stones or other structural abnormalities are suspected, imaging studies such as an ultrasound or CT scan of the urinary tract may be conducted. These diagnostic steps help to pinpoint the exact reason for the white blood cells in the urine, allowing for targeted management.
When to Consult a Healthcare Provider
Detecting white blood cells in your urine warrants a consultation with a healthcare provider. Even if there are no noticeable symptoms, an elevated white blood cell count can signal an underlying issue that requires attention. Ignoring these findings could lead to the progression of an infection or other health problems.
It is particularly important to seek medical advice if new symptoms arise, such as pain during urination, increased urinary frequency, cloudy or foul-smelling urine, fever, or back pain. Self-diagnosis or attempting to treat the condition without professional guidance is not advisable. A medical professional can accurately diagnose the cause of white blood cells in your urine and recommend the most appropriate course of action.