Leukocytes in Urine: What You Need to Know

Your urine sample lab results just came back from your urinalysis test. High levels of leukocytes in urine were detected in your urine and your doctor mentioned it may possibly be a sign of a urine infection. He has ordered further testing. Unsure what leukocytes are, you Google the term and your search results leave you more confused than ever.

Should you be concerned about blood cells in urine? What are leukocytes and why do they matter?

What Does it Mean to Have High Leukocytes in Urine?

Leukocytes are more commonly known as white blood cells, a type of immune cell made inside bone marrow. They are found in blood and lymph tissue and help the body fight off infections and disease. It’s natural to find small amounts of leukocytes in urine.

Leukocytes can be divided into five types: basophils, neutrophils, eosinophils, monocytes, and lymphocytes. Leukocyte levels can be measured through a blood test or urinalysis test. High levels of leukocytes in either the blood or the urine indicate that you may have an infection. Regardless of which test is performed, higher-than-normal leukocyte levels mean something may be wrong and your doctor may order further tests.

Common Leukocytes in Urine Causes

Though commonly associated with urinary tract infections, elevated leukocytes in urine may be a sign of other issues as well. Here are a few:

Bladder Infection

A urinary tract infection (UTI) is an infection involving any part of the urinary tract and is the most common culprit when it comes to leukocytes in urine. Urinary tract infections are incredibly common and result in around 8.1 million doctor’s visits annually. The lower urinary tract includes the bladder and urethra. Infections of the bladder, called cystitis, are the most common type of UTI. About 80 percent of all UTI’s result from bacteria from the bowel reaching the urinary tract. Both genders are affected, though UTI’s are more common among women. Symptoms of cystitis (bladder infection) include pelvic pressure, blood in urine, lower abdominal pain, and frequent, painful urination.

Kidney Infection

High levels of leukocytes in urine may also indicate a kidney infection. A UTI that started in the urethra or bladder and spreads to the kidneys (one or both) becoming significantly more serious. Also known as pyelonephritis, a kidney infection may cause permanent and life-threatening damage, especially if bacteria spread to the bloodstream.

Symptoms include fever, chills, back, side, abdominal, or groin pain, smelly or cloudy urine, nausea and vomiting, puss or blood in the urine, burning sensation when urinating, a persistent urge to urinate, and frequent urination. Antibiotics are required to treat kidney infections and hospitalization may be necessary.

Urinary Tract Infection

As mentioned previously, a urinary tract infection (UTI) is an infection in any part of the urinary tract: urethra, bladder, ureters, or kidney. An untreated UTI may lead to complications like recurrent infections, permanent kidney damage, the risk of delivering a low birth weight or premature baby, urethral narrowing in men, or life-threatening sepsis. UTI symptoms include fatigue and shakiness, cloudy or unusual-smelling urine, fever or chills, frequent urge to urinate, and lower back or abdominal pain. If a urinalysis test shows increased levels of leukocytes, there’s a very good chance you have a UTI.

Leukocytes in Urine but no Infection

Still, leukocytes in urine are not a sure-fire way to diagnose an infection. It’s possible for healthy individuals to have elevated levels of leukocytes in their blood and urine. Sometimes, false test results may happen because of incorrect testing techniques or poor hygiene while taking the sample. Other times, leukocytes in urine but no infection indicate that something else is wrong with the body and more testing is needed to find the cause.

Kidney Stones

Leukocytes in Urine

If an infection is not the culprit, leukocytes may indicate the presence of kidney stones. Kidney stones are hard mineral and salt deposits formed inside your kidneys. They may end up in the urethra, making it difficult for urine to pass. The blockage is the perfect recipe for bacteria and infections. There are several factors that increase your risk of developing kidney stones:

  • You have more crystal-forming substances in your urine that your body can dilute.
  • Your urine doesn’t contain the necessary substances that prevent crystals from combining.

Apart from high levels of leukocytes in your urine, other signs or symptoms of kidney stones include severe pain, cloudy or foul-scented urine, nausea and vomiting, blood in urine, difficulty urinating and urinating in small amounts, as well as pain alongside fever and chills.

Kidney stones come in several varieties (calcium stones, uric acid stones, struvite stones, or cystine stones) and most pass without surgical intervention. A kidney stone lodged along the urinary tract, however, may cause infection and other complications. Surgery may be your best option.

Certain Cancers

There are times when high levels of leukocytes in urine indicate a very serious problem, such as cancer. Malignant (cancerous) tumors growing in the kidneys or the bladder may cause leukocytes to manifest in urine. Another possibility is bladder cancer. Bladder cancer is fairly common and symptoms are often mistaken for a UTI. Blood in urine is a tell-tale sign to look for, though keep in mind that blood in urine may occur for a variety of reasons and does not necessarily mean you have cancer. While red blood cells are more common in the urine of a bladder cancer patient, there have also been cases where white blood cells (leukocytes) have led to a bladder cancer diagnosis. If caught early, bladder cancer is treatable.

Sickle Cell Anemia

An inherited condition, sickle cell anemia is when the body doesn’t have the healthy red blood cells needed to transport sufficient supplies of oxygen throughout the body. Instead of being flexible and round, the red blood cells of a sickle cell anemia patient are irregularly shaped crescent moons (sickles). There’s no cure and it’s usually diagnosed in infancy. Unfortunately, sickle cell anemia may lead to a variety of complications, including stroke, organ damage, acute chest syndrome, priapism in men, pulmonary hypertension, leg ulcers, and gallstones. Elevated levels of leukocytes may potentially indicate a blood disease like sickle cell anemia.

Diabetic Nephropathy

A kidney disease that may occur in people with diabetes, diabetic nephropathy may lead to end-stage renal disease (ESRD) as well as long-term kidney damage. Forty to 50 percent of ESRD cases are related to diabetic nephropathy and patients require dialysis. Diabetic nephropathy develops slowly and it damages the kidney’s filtering system over time. Also called diabetic kidney disease, it affects patients with either Type 1 or Type 2 diabetes. Studies have shown that an elevated leukocyte count, even in the normal range, may be associated with Type 2 Diabetes complications. If you have diabetes and your urinalysis test shows elevated levels of leukocytes, discuss this with your doctor.


A chronic autoimmune disease, Lupus can wreak havoc on the body. In an autoimmune disease, the body cannot differentiate between invaders (germs, bacteria, and viruses) and healthy body tissue. Autoantibodies attack and destroy the healthy tissue. About 1.5 million Americans have Lupus and it can range from mild to life-threatening. While there is no cure, effective treatments are available to help patients live their best life. Urinalysis is done to test for Lupus and leukocyte levels will be examined as part of that test. While leukocytes in urine alone are not an indicator of Lupus, it may provide your doctor with vital clues.


Pelvic trauma may lead to increased leukocyte levels. Other types of trauma may result in a blockage in the urinary tract system and further complications. Any type of damage to the urinary tract system can result in leukocytes in urine. Discuss injuries with your doctor.

Blood Vessel Damage

Blood vessels are a vital part of the circulatory system, responsible for transporting blood throughout the body. Hypertension and diabetes both may cause blood vessel damage and the results are serious. Kidney disease or kidney failure, vision loss or blindness, stroke, heart attack, erectile dysfunction, poor circulation, nerve damage, and a weakened immune system are a few potential consequences. A urine test for leukocytes may detect some of these issues and lead to a further medical investigation

Certain Medications

Lastly, a common cause of leukocytes in urine is the medication you take. Certain pain medications and blood thinners may cause elevated leukocytes. Your lab results may merely indicate your body’s reaction to a medication that increased your white blood cell production. Corticosteroids, allopurinol, chloroform, aspirin, quinine, heparin, triamterene, and epinephrine are some drugs that may affect your leukocyte levels to register higher-than-desired in your urinalysis test.

Leukocytes in Urine Test

Urinalysis is a series of lab tests: physical, chemical, and microscopic. This process is used to detect and measure various substances found in urine.

When Should You Get Tested for Leukocytes in Urine?

A urinalysis test may be ordered to monitor a patient’s overall health, to diagnose a medical condition, or to monitor an existing medical condition. This may occur at an annual checkup or may be ordered at the doctor’s discretion if a patient is experiencing abdominal or back pain, blood in urine, frequent or painful urination, or a variety of other issues. If a doctor suspects a urinary tract infection, liver disease, diabetes, or kidney disease, they’ll order a urinalysis test to check for leukocytes and other vital clues.

Where to Get Tested?

Urinalysis is a laboratory test, so it takes place at a hospital, medical clinic, doctor’s office, or specialized testing facility with access to a lab. The LabCorp website allows users to find a laboratory near them and book an appointment online. The Personalabs website also offers a search function to help users locate a urinalysis testing center in their state.

How the Test Works

One to two ounces of urine is collected in a clean, clear container. The sample is then sent to a lab for analysis. First, a visual test is performed. A lab technician examines the sample for color and clarity. Urine should be clear. Cloudiness or unusual color or odor may be a sign of a problem.

Next, urine is chemically tested using the dipstick test. A chemical strip on a thin plastic testing stick changes colors if certain substances are present in the urine or if the levels are high. The dipstick tests checks for acidity (pH), concentration, protein, sugar, ketones, bilirubin, evidence of infection, and blood.

Lastly, urine is examined under a microscope to identify white blood cells (leukocytes), red blood cells (erythrocytes), crystals, casts, and bacteria or yeast. High levels of any of these will lead to additional testing. Test results are examined by your doctor and may or may not require a follow-up appointment. A urinalysis test alone doesn’t equal a definitive diagnosis.

Leukocytes in Urine No Nitrates

If leukocytes and nitrates are found in urine, it’s most likely that a patient has a urinary tract infection. If your urinalysis test detects leukocytes but not nitrates, you could have a false positive result. Or, you may still have an infection or inflammation, be pregnant, or have a condition called hematuria. Sexual intercourse can increase the risk of a UTI and lead to leukocytes in urine.

The Possibility of False Test

Sometimes, false positive test results occur when there was an error in the urinalysis technique or—more likely- proper hygiene procedures were not followed when collecting the urine sample. In order to ensure accurate results, make sure to properly clean your genitals and the area immediately surrounding your urethral opening with a wipe or clean water. Allow urine to flow for 2 seconds before you start collecting the sample.

Final Thoughts

Leukocytes, or white blood cells, naturally appear in urine in small amounts. High levels of leukocytes, indicated by a urinalysis test, often mean a patient has a urinary tract infection. However, that’s not always the correct diagnosis. While urinalysis is an excellent place to start, it’s also just the beginning. Your doctor will take your test results and work with you to get to the bottom of your symptoms, ordering further tests if needed.