Urinary casts are tiny tube-shaped particles that can be found when urine is examined under the microscope during a test called urinalysis.
Urinary casts may be made up of white blood cells, red blood cells, kidney cells, or substances such as protein or fat. The content of a cast can tell your health care provider whether your urine is healthy or abnormal.
Hyaline casts; Granular casts; Renal tubular epithelial casts; Waxy casts; Casts in the urine; Fatty casts; Red blood cell casts; White blood cell casts
How the test is performed
The urine sample you provide may need to be from your first morning urine. The sample needs to be taken to the lab within 1 hour.
A clean-catch urine sample is needed. The clean-catch method is used to prevent germs from the penis or vagina from getting into a urine sample. To collect your urine, the health care provider may give you a special clean-catch kit that contains a cleansing solution and sterile wipes. Follow instructions exactly so that the results are accurate.
How to prepare for the test
No special preparation is needed.
How the test will feel
The test involves only normal urination. There is no discomfort.
White blood cell (WBC) casts are more common with acute kidney infections.
Your health care provider will tell you more about your results.
What the risks are
There are no risks with this test.
Gerber GS, Brendler CB. Evaluation of the urologic patient: history, physical examination, and urinalysis. In: Wein AJ, Kavoussi LR, Novick AC, et al., eds. Campbell-Walsh Urology. 10th ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 3.
McPherson RA, Ben-Ezra J. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 22nd ed. Philadelphia, Pa: Elsevier Saunders; 2011:chap 28.
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, Bethanne Black, and the A.D.A.M. Editorial team.