Which of the following components would NOT be considered an artifact in urine analysis?

Epithelial cells are not considered artifacts in urine analysis because they are a normal component found in urine, often indicating the condition of the renal tubules and urinary tract. Epithelial cells can originate from various locations, such as the bladder, urethra, or renal tubules and their presence in urine can provide important diagnostic information regarding the health of these tissues.

In contrast, artifacts like starch, oil droplets, and air bubbles are typically not biological substances present in urine due to pathological processes. Starch may come from contamination, oil droplets could originate from various sources in the environment or handling of samples, and air bubbles generally form during sample collection or processing. Therefore, these artifacts do not provide relevant clinical information regarding a patient's condition, while epithelial cells can serve as indicators of potential issues within the urinary system.