What type of casts are considered normal in urine?

Hyaline casts are considered normal constituents in urine, particularly when observed in low quantities such as 0 to 2 casts per high-power field. They are formed from the homogenization of proteins found in the tubular fluid, and their presence can indicate normal renal function or mild dehydration. These casts can be more prominent during periods of increased physical activity or dehydration but do not indicate any underlying pathological condition when they appear in small numbers.

Other types of casts typically indicate some level of pathology or higher levels of certain conditions. Granular casts, for instance, usually indicate some degree of renal damage or disease, while red blood cell casts suggest glomerular bleeding or injury. Fatty casts arise in conditions affecting lipid metabolism and usually indicate significant pathology as well. Therefore, the presence of 0-2 hyaline casts aligns with normal findings in a urinalysis.