Which of the following substances is considered a urine artifact?

Pollen grains are classified as urine artifacts because they can be present in urine samples through external contamination rather than originating from the urinary tract or bodily processes. These granules are not typically produced by the body and are often inhaled or deposited from environmental sources, such as plants, when urine is collected.

In contrast, red blood cells, white blood cells, and urinary casts are formed as a result of physiological or pathological processes within the body. Red blood cells and white blood cells can indicate underlying health issues when found in urine, such as bleeding or infection. Urinary casts are cylindrical structures formed in the renal tubules and can suggest specific renal conditions depending on their type and structure. Since pollen does not reflect any internal body activity, it is recognized as an artifact rather than a true representation of urinary pathology.