Urinalysis - The Carter Center

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CASTS
• Formed by precipitation of proteins, and aggregation of cells within
the renal tubules. Most of them dissociate in alkaline urine, and
diluted urine (specific gravity ≤ 1.010) even in the presence of
proteinurea. Most of them are transparent. Thus to look them
clearly, it is important to lower the condenser and close (partially) the
diaphragm. Look them under 10 x (low power objective) of the
microscope. There are different kinds of casts based on their shape
and content (morphologically) may be grouped in to the following.
a. Hyaline Casts
• Normal range: 0-2/HPF
• Appearance
- Transparent (clear), cylindrical shape
- Have parallels side with slightly round ends
- Their appearance in urine depends on rate of urine flow, i.e.
many hyaline casts are seen when the flow rate is slow, and
are not seen in alkaline urine mostly; and as the degree of
proteinurea is high, there concentration also increase.
Clinical Implication
Presence of large number of hyaline casts may show possible damage
of glomerular capillary membrane. This damage permits leakage of
protein through glomerulus and result in precipitate and gel formation
(i.e. hyaline casts) in the tubule. Thus this may indicate:
• Nephritis
• Meningitis
• Chronic renal disease
• Congenital heart failure
• Diabetic nephropathy