Microscopy of Urine Sediment: Waxy Casts
Waxy casts are dense, homogeneous formations that develop from hyaline casts remaining for extended periods in the distal tubules and collecting ducts. Their appearance resembles fragments of wax candles: clearly defined, cylindrical in shape, they can be straight or curved, short or long.
These casts are generally wider than hyaline casts but vary in size—from very narrow to extremely wide. Their color depends on urinary pigments: most often yellow or yellowish; however, in colorless urine, they also remain colorless. In prolonged renal hematuria, waxy casts can be stained by hemoglobin and its breakdown products.
A distinctive feature of waxy casts is the presence of cracks or fissures on their surface, as well as bay-like indentations along their contour.
The detection of waxy casts in urine sediment is usually associated with nephrotic syndrome of various etiologies, making them an important diagnostic marker.
🙏 Photos and description kindly provided by biologist Anna Feditskaya, Luhansk.
