Which of the following indicates a possible UTI in a urinalysis?

The presence of white blood cells (WBCs) in a urinalysis is a significant indicator of a possible urinary tract infection (UTI). When an infection occurs in the urinary tract, the body responds by sending WBCs to the site of infection. This immune response results in an increased number of WBCs in the urine, which is measured during a urinalysis. Thus, finding WBCs suggests that the body's immune system is reacting to a potential infection, commonly seen in cases of UTIs.

Other indicators such as high levels of epithelial cells or a high red blood cell (RBC) count may suggest different issues. For example, an elevated count of epithelial cells can be associated with a variety of conditions but does not specifically point to a UTI. Similarly, a high RBC count could indicate bleeding in the urinary tract but is not a direct marker for infection. The presence of low levels of bacteria would not signify a UTI; in fact, a UTI is often confirmed by the presence of bacteria in the urine. Therefore, the presence of WBCs is the most relevant criterion for diagnosing a UTI in this context.