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Urinalysis (cont.)

What Are Cells Detected by Urinalysis Results?

Some of the cells detected in a urinalysis are epithelial cells, red blood cells, and white blood cells. Epithelial cells are the cells lining many structures in the body, such as the urethra, bladder, ureters, vagina, or skin. The presence of epithelial cells in the urine may represent contamination of the sample; however, these cells in urine may also be associated with an inflammation or infection of the urethra or bladder.

With microscopic analysis, the quantity of cells in the urine can be estimated, and the number of cells (white blood cells, red blood cells, epithelial cells, and bacteria) in the urine is reported as the number of cells seen in one high power field (number of cells viewed in one field under the highest magnification of the microscope lens).

What Are Red Blood Cells in the Urine?

The presence of intact red blood cells in the urine usually signifies a source of blood loss in the lower part of the urinary tract (urethra, bladder, ureters). Blood in the urine may be visible by the naked eye (gross hematuria) or only under the microscope (microscopic hematuria). Gross hematuria may be related to trauma to the bladder or urethra, bladder tumors, or hemorrhage.

Microscopic hematuria (red blood cells seen only under microscope) may indicate an infection in the lower urinary tract or a kidney stone. Sometimes, red blood cells may be seen in the form of red blood cell casts, and this generally points to the kidney as the source, such as an inflammation of the kidney (glomerulonephritis).

What Are White Blood Cells in the Urine?

White blood cells (or leukocytes) in the urine may be detected in the microscopic analysis of urine. In general, the presence of these cells in the urine is suspicious for a urinary tract infection (UTI). Other supportive evidence of a UTI may include bacteria in the urine, leukocyte esterase and nitrite on the dipstick, and clinical evidence of urinary tract infection.

Medically reviewed by Michael Wolff, MD; American Board of Urology

"Urinalysis in the diagnosis of kidney disease"

"Sampling and evaluation of voided urine in the diagnosis of urinary tract infection in adults"

"Evaluation of and initial approach to the adult patient with undifferentiated hypotension and shock"

Last Editorial Review: 8/5/2015

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