Hyaline casts are the type most commonly seen in the urine sediment. A few hyaline casts may occasionally be found in normal urine, and hyaline casts may be seen after strenuous exercise, during fever, or when undergoing diuretic therapy.
Pathologically, hyaline casts may be seen with congestive heart failure, and may be seen together with other types of casts in a variety of renal diseases.
Hyaline casts have a refractive index similar to the urine in which they are suspended. For this reason, hyaline casts will appear almost invisible under brightfield microscopy, but are easily seen with the use of phase-contrast microscopy.