Leukocytes (white blood cells - WBC) are the cells of the immune system that protect the body against both infectious diseases and foreign invaders. When your body fights infection, your immune system triggers the production of white blood cells. Leukocyte esterase is an enzyme that is produced by leukocytes.
What does Leukocytes in Urine test mean?
A few white blood cells are normally present in urine and are generally not a cause of concern as they may not indicate an infection. High levels of WBCs in the urine typically suggest inflammation or infection. This occurs when the body tries to fight off an infection, typically in the urinary tract.
When the number of WBCs in urine increases significantly, it could indicate possible inflammation or infection, for example, a urinary tract infection.
The urinary tract is the body’s drainage system for removing urine. It comprises two kidneys, two ureters (thin tubes of muscle that connect your kidneys to your bladder), a bladder (a hollow, muscular, balloon-shaped organ that stores urine), and a urethra (the tube that carries urine from the bladder and allows urine to exit the body during urination). Urinary tract infections typically occur in the bladder or the urethra. Leukocytes in the urine could also suggest a kidney infection (e.g., kidney stones), a tumor in the pelvis, or some other type of blockage in the urinary tract.
How to test Leukocytes in Urine?
A urine dipstick test (also known as urinalysis or a UA test) can be used to check urine leukocyte levels. A urine dipstick is a narrow plastic strip with one or more reagent pads. A leukocyte dipstick test can check the leukocyte levels in a urine sample. When dipped in the urine, the leukocyte reagent pad changes color in response to the level of leukocyte esterase in the urine. The color of the resulting pad is compared against the color key to interpret the results.
The leukocyte esterase UA test is a simple, easy-to-perform, and quick way to determine signs of infections. The test can easily be performed at home, and the results are ready in two minutes.
Leukocyte reagent urine test strips typically pair with other reagent pads and can be purchased as a 2-parameter UTI test or a multiparameter 10-parameter urinalysis strips.
How to read Leukocytes in Urine dipstick test?
The urine dipstick test for Leukocytes should be read precisely at 2 minutes in good lighting. Note the color of the reagent pad and compare it with the color key provided by the manufacturer to interpret the results.
Normal Range of Leukocytes
A few white blood cells are normally present in urine and yield a negative result.
The normal leukocyte count in urine is less than 5 cacells/HPF, in which case the leukocyte esterase dipstick test indicates a negative result (i.e., below traceable limits of 15 cacells/µL). A negative result is indicated by a white, off-white, or a light shade of cream color on the reagent pad. If you notice little to no change in the pad color after dipping in the urine specimen, it generally implies a negative result (i.e., normal leukocyte range).
Positive Leukocytes in urine
If the pad color is no longer white/off-white and turns cream, brown, or a shade of purple, it indicates a positive result for leukocytes (high leukocyte levels in urine).
Trace Leukocytes in urine (15 cacells/µL) change the color of the reagent pad on the dipstick to a beige (light brown) color.
As the concentration of leukocytes increases in the urine, the pad color will change from cream to dark/bright shades of purple.
Small leukocyte levels (75 cacells/µL) are indicated by a light purple color on the reagent pad.
Moderate levels of leukocytes (125 cacells/µL) are indicated by the purple color of the reagent pad.
The maximum detectable level on a urine test strip is 500 cacells/µL of leukocytes, resulting in a dark purple color of the reagent pad.
How to interpret results?
A positive test result for leukocytes in urine indicates a possible infection or inflammation in the body (particularly in the urinary tract). A combination of positive results for both Leukocytes and Nitrite in urine is a good indicator of urinary tract infections (UTI). A significant number of white blood cells in the urine and a positive nitrite test indicate bacteriuria (bacteria in urine) and a urinary tract infection. Women are at a greater risk for urinary tract infections and, therefore, are more likely to have leukocytes in their urine. Pregnant women have an even higher risk for UTIs. Men can develop these infections, too. Having an enlarged prostate, for example, raises the risk of UTIs in men. Anyone with a compromised immune system may also be at higher risk for infection.
You may also find positive leukocytes in urine before the onset of any physical symptoms of an infection. For example, scientific studies indicate that urine gets an influx of leukocyte esterase before any physical or noticeable signs of cold or other infections. A positive leukocyte test can also mean the body has not recovered from a previous workout and might require some rest.
So, keeping track of leukocytes is an excellent way to know about your health and body’s needs.
Ruth Keller is a seasoned medical reporter and healthcare writer with over 25 years of experience in the industry. With a passion for uncovering and sharing the latest developments in medicine and healthcare, Ruth has established herself as a trusted and respected voice in the field.
With a deep understanding of healthcare's scientific, social, and political dimensions, Ruth is known for her ability to translate complex medical concepts into clear and accessible language.
As a senior writer for Diagnox, Ruth has the opportunity to work with a team of professionals from various scientific backgrounds and share her knowledge with a broad audience. Whether she is writing about the latest research on disease prevention or the importance of proper nutrition, Ruth is always looking for ways to educate and empower readers to take control of their health.
Ruth continues her passion for healthcare using her extensive knowledge and expertise to inform and educate the public on the most pressing issues in healthcare.
About the Reviewer
This blog was
Technically reviewed by:
H. Ali, Ph.D.
Hussnain Ali received his Ph.D. degree in EE in 2015 from the University of Texas at Dallas, USA. He is the co-founder and the Chief Executive Officer (CEO) at Diagnox Health, Plano, TX 75024, USA, and a visiting research scientist at the University of Texas at Dallas. His academic and industry experience spans over 15 years in organizations like the Center for Advanced Research in Engineering, The University of Texas at Dallas, and Harman/Samsung. He has served as a co-PI on an RO1 grant from the National Institutes of Health (NIH). His research interests include biomedical devices, auditory rehabilitation, and cochlear implants. He has authored and co-authored over 70 international publications and has been awarded multiple US patents. His latest work at Diagnox encompasses the development of innovative healthcare and wellness products/solutions that provide convenient and affordable at-home screening/diagnosis. He aims to bridge conventional clinical diagnostic products with Artificial Intelligence (AI) and contemporary data-centric technologies to modernize the healthcare and wellness industry.
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