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[Infographic] Types of Leukocytes: Amount and Function

A complete blood cell (CBC) test often includes a measurement of the level of leukocytes, or white blood cells (WBCs). Higher levels of leukocytes in the bloodstream may indicate an infection. This is because WBCs are part of the immune system, and they help fight off disease and infection. Leukocytes may also be found in a urinalysis, or a urine test. High levels of WBCs in your urine also suggest that you have an infection. In this case, your body is trying to fight off an infection somewhere in your urinary tract. Usually, that means the bladder or the urethra, which is the tube that carries urine from the bladder. Leukocytes in the urine could also suggest a kidney infection.

Why do they appear?

Infections or obstruction in the urinary tract or bladder may cause you to have an increased amount of leukocytes in your urine. Infections may be more severe if you’re pregnant, which increases the odds of developing problems such as urinary tract infections (UTIs). If you’re pregnant and have an infection in your urinary tract, it’s important to receive treatment because it could complicate your pregnancy.

You’re at risk for developing a bacterial infection in your bladder if you hold your urine too long before relieving yourself. Repeatedly holding in urine can stretch the bladder too much. Over time, that makes your bladder less likely to empty fully when you go to the bathroom. When urine remains in the bladder, it raises the chances that bacteria will increase in number, which may lead to a bladder infection. Uncomplicated cystitis is another name for a urinary infection that’s limited to the bladder in healthy people who aren’t pregnant. Kidney stones, a tumor in the pelvis, or some other type of blockage in the urinary tract may also cause more leukocytes to appear.


Leukocytes in urine don’t necessarily cause symptoms on their own. If you do have leukocytes in your urine, your symptoms will vary depending on the condition that is causing the leukocytes to build up in your urine.

The symptoms of a UTI include:

  • a frequent urge to urinate
  • a burning sensation when urinating
  • cloudy or pink-tinted urine
  • strong smelling urine
  • pelvic pain, especially in women

Obstructions in the urinary tract can cause a range of symptoms depending on the location and type of obstruction. In most cases, the main symptom is pain on one or both sides of the abdomen. Kidney stones may cause similar symptoms as a UTI but may also include nausea, vomiting, and intense pain.


If you’re healthy, you can still have elevated leukocytes in your bloodstream and urine. A normal range in the bloodstream is between 4,500-11,000 WBCs per microliter. A normal range in the urine is lower than in the blood, and may be from 0-5 WBCs per high power field (wbc/hpf). If your doctor suspects you have a UTI, they’ll likely ask you to provide a urine sample. They’ll test the urine sample for:

  • WBCs
  • red blood cells
  • bacteria
  • other substances

You’re bound to have a few WBCs in your urine even when you’re healthy, but if a urine test identifies levels above 5 wbc/hpf, it’s likely you have an infection. If bacteria are detected, your doctor may perform a urine culture to diagnose the type of bacterial infection you have.

A urine test can also aid in the diagnosis of kidney stones. An X-ray or CT scan can help your doctor see the stones.

One of the easiest ways to help keep your urinary tract free of infections or kidney stones is to stay hydrated. Drink several glasses of water per day, but talk with your doctor about what amount of water is best for you. If you’re frail or you have a condition such as heart failure, your doctor may recommend that you limit your fluid intake. If you’re active or pregnant, you may need to drink more water every day.