Urinary casts are tiny tube-shaped particles that can be found when urine is examined under the microscope during a test called
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
How the Test is Performed
The urine sample you provide may need to be from your first morning urination. The sample needs to be taken to the lab within 1 hour.
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.
Why the Test is Performed
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:
Glomerular disease Interstitial kidney disease
- Kidney infections
The absence of cellular casts is normal. The presence of a few hyaline casts is also normal. Hyaline casts are the most common type of urinary casts. They're made up of a protein call uromodulin and are often the result of conditions such as dehydration and strenuous exercise, as well as chronic kidney failure.
What Abnormal Results Mean
Abnormal results may include:
- Fatty casts are seen in people who have lipids in urine. This is most often a complication of
- Granular casts are a sign of many types of kidney diseases.
- Red blood cell casts mean there is a microscopic amount of bleeding from the kidney. They are seen in many kidney diseases.
- Renal tubular epithelial cell casts reflect damage to tubule cells in the kidney. These casts are seen in conditions such as
renal tubular necrosis, viral disease such as cytomegalovirus (CMV) nephritis, and kidney transplant rejection.
- Waxy casts can be found in people with advanced kidney disease and
long-term (chronic) kidney failure.
- White blood cell (WBC) casts are common with acute kidney infections and interstitial nephritis.
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: Johnson RJ, Floege J, Tonelli M, eds. Comprehensive Clinical Nephrology. 7th ed. Philadelphia, PA: Elsevier; 2024:chap 72.
Riley RS, McPherson RA. Basic examination of the urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 29.
Review Date: 20/08/2023
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