Hyaline Casts in Urine: What’s Normal vs. High? (2024)

Urine casts result from protein or other materials that conform to the shape of the distal tubules of the kidneys and then get excreted in the urine. They are seen using a microscope's low power field (LPF) during a urine examination (urinalysis) and often indicate kidney disease. Hyaline casts result from a specific protein called "uromodulin."

Sometimes, hyaline casts result from dehydration or strenuous exercise and do not require further testing. Higher than normal hyaline cast levels may prompt additional laboratory and imaging tests to determine if the hyaline casts are due to kidney disease.

This article will help you understand the difference between "normal" and "high" hyaline cast ranges on a urinalysis and what each means for your health.

Why Are Hyaline Casts in Urine?

Casts are created in the kidney's distal tubules, or collecting ducts, where granular or waxy substances called proteins build up. Often, urine casts can indicate possible kidney disease.

Hyaline casts are composed of specific proteins created by the renal cells, which are known as uromodulin. Because hyaline casts tend to be evident in urine samples collected to examine the cause of slow urinary flow, they can be present without evidence of kidney disease.

Dehydration, diuretic use, or strenuous exercise are possible reasons for hyaline casts when there is no evidence of kidney disease.

Physiological Causes

Hyaline casts are often seen in a urinalysis test as a result of slow or sluggish urinary flow due to:

• Intense exercise
• Dehydration
• Fever (which could cause dehydration)
• Diuretic use

Pathological Causes

If the number of hyaline casts seen under a microscope's low power field (LPF) in a urinalysis test is higher than two hyaline casts, a healthcare provider may perform additional testing for the following conditions:

• Kidney infection (e.g., pyelonephritis)
• Chronic renal disease (e.g., glomerular disease)
• Congestive heart failure
• Kidney damage from diabetes (i.e., diabetic nephropathy)
  

Hyaline Cast Results From Urinalysis

The identification of casts in a urinalysis may pose concerning evidence of disease. However, hyaline casts are slightly different because they do not always indicate kidney disease. Generally, zero to two hyaline casts in LPF are not cause for concern.

Uromodulin, the protein created by the renal cells that form hyaline casts, may show up in a urinalysis due to many conditions, such as:

• Dehydration
• Rigorous exercise
• Diuretic use
• Kidney infection, like pyelonephritis
• Chronic kidney disease

Normal Range of Hyaline Casts

Hyaline casts are seen under a microscope's LPF. Generally, zero to two hyaline casts/LPF is considered a normal range. A healthcare provider will typically determine whether you need further testing regarding the presence of hyaline casts based on your health history and status.

High Range of Hyaline Casts

Generally, casts are indicative of possible kidney disease. However, hyaline casts are slightly different and can be seen with any possible kidney disease. If more than two hyaline casts/LPF are identified, your healthcare provider should perform more testing to ensure there is no evidence of kidney disease.