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 help tell your health care provider whether your kidney 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
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 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.
No special preparation is needed.
The test involves only normal urination. There is no discomfort.
Your provider may order this test to see if your kidneys are working properly. It may also be ordered to check for certain conditions, such as:
The absence of cellular casts is normal. The presence of a few hyaline casts is also normal.
Abnormal results may include:
Your provider will tell you more about your results.
There are no risks with this test.
Judd E, Sanders PW, Agarwal A. Diagnosis and clinical evaluation of acute kidney injury. In: Feehally J, Floege J, Tonelli M, Johnson RJ, eds. Comprehensive Clinical Nephrology. 6th ed. Philadelphia, PA: Elsevier; 2019:chap 68.
Riley RS, McPherson RA. Basic examination of the urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 28.
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, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.