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RBC - urine
Definition
The RBC urine test measures the number of red blood cells in a urine sample.
Alternative Names
Red blood cells in urine; Hematuria test; Urine - red blood cells
How the Test is Performed
A clean-catch urine sample is needed.
To obtain a sample, boys and men should wipe the head of the penis clean. Girls and women need to wipe between the vaginal "lips" (labia) with soapy water and rinse well. Your doctor may give you a special clean-catch kit that contains a cleansing solution and sterile wipes.
Urinate a small amount into the toilet bowl to clear the urethra of any contaminants. Then, collect a sample of urine in a clean or sterile container. About 1 - 2 ounces of urine is needed for a test. Remove the container from the urine stream without stopping the flow. You may finish urinating into the toilet bowl. Take the sample to the lab.
For infants, the genital area is cleaned and dried, and then a collection device is attached to collect the urine. If you are asked to collect the urine, be sure the collection device is attached securely to prevent leakage. After your baby has urinated, the urine (at least 20 cc) is placed in a sterile container.
How to Prepare for the Test
No special preparation is necessary for this test, but if the collection is being taken from an infant, a couple of extra collection bags may be necessary.
How the Test Will Feel
The test involves only normal urination, and there is no discomfort.
Normal Results
A normal result is 4 RBC/HPF (red blood cells per high power field) or less.
The examples above are common measurements for results of these tests. Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results.
What Abnormal Results Mean
Greater than normal numbers of red blood cells in the urine may be due to:
- Acute tubular necrosis
- Cystitis (bladder infection)
- Glomerulonephritis
- Interstitial nephritis
- Pyelonephritis (kidney infection)
- Kidney trauma
- Kidney tumor
- Kidney stones
- Menstrual bleeding
- Prostatitis
Additional conditions under which the test may be performed:
- Alport syndrome
- Kidney vein thrombosis
References
Landry DW, Bazari H. Approach to the patient with renal disease. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 116.
Reviewed By: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
