What Causes Leukocytes in Urine?

Medically Reviewed by Minesh Khatri, MD on January 27, 2022
3 min read

If your doctor tests your urine and finds too many leukocytes, it could be a sign of infection.

Leukocytes are white blood cells that help your body fight germs. When you have more of these than usual in your urine, it's often a sign of a problem somewhere in your urinary tract.

Some of the most common reasons for leukocytes in urine, and other symptoms you might see with them, include:

Your urinary tract includes your kidneys, bladder, and ureters (tubes that carry urine from the kidneys to the bladder). An infection in your urinary tract is the most likely cause of leukocytes in your urine. Any time you have an infection, your immune system ramps up production of these cells to fight off the bacteria.

More than half of women and about 1 in 5 men will get a UTI at some point in their lives. Signs that you have one are:

  • Pain or burning when you pee
  • You need to go more often than usual
  • Cloudy or foul-smelling urine
  • Pain in your belly, back, or side
  • Nausea and vomiting

Your doctor can treat a UTI with antibiotics. A few days to a week on these drugs should clear up the infection.

How long you stay on the medicine depends on how severe your infection is, how often you get UTIs, and any other medical problems you have. To help ease pain while the infection clears, take an over-the-counter pain reliever or put a heating pad on your back or belly.

Make sure to take the whole antibiotic dose that your doctor prescribed. Otherwise, you could leave some bacteria alive, and they could reinfect you. That new infection could be harder to knock out with antibiotics. If your UTIs keep coming back, your doctor might put you on low-dose antibiotics for several months.

Call your doctor if you have symptoms such as:

If you still have symptoms after antibiotics, check in with your doctor again. You may need more treatment.

Kidney stones are crystals that form when calcium and other minerals build up in your urine. They can be as small as a pea or as big as a golf ball. Larger kidney stones can block the flow of urine.

Kidney stones cause symptoms such as:

  • Sharp pain in your belly, side, back, or groin
  • Blood in your urine that looks red, pink, or brown
  • An urgent need to pee
  • Pain when you pee
  • Cloudy or foul-smelling urine

Call your doctor right away if you think you have a kidney stone or if the pain is severe.

A small kidney stone might pass on its own. Drinking extra water can help flush it from your system. Over-the-counter pain relievers will help make you more comfortable until the stone is gone.

A urologist can remove bigger stones. A treatment that aims powerful waves at the stone from a machine outside your body can break it up. Afterward, the smaller pieces pass in your urine.

Another stone removal method passes a scope into the kidney through your bladder, or through a small opening in your back or side. The doctor will use special tools to break up the stone and remove it from your body.

Inflammation in your body triggers the release of leukocytes. That inflammation can come from an injury, infection, or disease.

Interstitial nephritis and cystitis are two conditions that cause inflammation in your urinary tract. Interstitial nephritis is a disease where inflammation involving the kidney causes that organ to not work as well. Cystitis is inflammation of your bladder, often from a urinary tract infection, but the bladder can also be inflamed without infection (interstitial cystitis).

If you have either one of these problems, you may notice symptoms like:

  • Increased urge to pee
  • Peeing more often than usual
  • Blood in your urine
  • Fever
  • Nausea and vomiting
  • Swelling on the feet

Keep in mind that if you have interstitial nephritis, there often aren't any symptoms until the disease is very advanced.

Call your doctor if you have these symptoms. If an infection is to blame, you'll get antibiotics. Other causes may need treatment with corticosteroids or other medicines.