Fibers are urinary artifacts and should be differentiated from casts. They are typically flat with dark, well-defined edges. Under polarized light, they are typically highly refractile.

Spermatozoa have a small, bulbous head with a long, thin tail that may detach.

May be seen as a contaminant following recent sexual activity in both sexes. Can also be seen in men with some genital diseases.

Starch granules are round with irregular indentation in the center. Under polarized light, they form “Maltese crosses.”

Starch is a contaminant found in many body powders.

Fat droplets are highly refractile and form a “Maltese Cross” pattern when polarized.

Can be artifactual from oils, creams, or lubricants. Otherwise seen in conditions causing lipiduria such as nephrotic syndrome.