Urinary casts are tiny tube-shaped particles made up of white blood cells, red blood cells, or kidney cells. They form in kidney structures called tubules. Casts are held together by a protein released by the kidney. The content of a cast can tell your health care provider whether your urine is healthy or abnormal.
Types of urinary casts include:
Red blood cell casts
Renal tubular epithelial casts
White blood cell casts
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
A clean-catch (midstream) urine sample is needed, preferably the first morning urine sample. For information on how to collect this sample, see: Clean-catch urine culture
How to prepare for the test
No special preparation is needed.
How the test will feel
The test involves only normal urination, and there is no discomfort.
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.
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.