What type of casts are described as nonpathogenic and granular?

Hyaline casts are considered nonpathogenic because they are often formed under normal conditions, particularly when urine is concentrated. They are composed primarily of protein and are clear and transparent, which allows for easier viewing under a microscope. Their presence can be attributed to factors such as dehydration or vigorous exercise, making them a common finding that typically does not indicate any underlying kidney disease.

In contrast, the other types of casts mentioned often have clinical significance. Waxy casts, for example, are associated with advanced renal disease and represent a degenerative form of granular casts. Fatty casts are often found in conditions involving lipiduria, such as nephrotic syndrome, and can indicate pathological changes in the kidneys. Cellular casts usually indicate inflammation or cellular damage within the renal tubules, reflecting underlying pathology. Thus, hyaline casts stand out as nonpathogenic and granular since they can appear in the absence of renal impairment, serving as a normal finding in urinalysis.