Which patient reached a PSA value above 100 ng/mL at any time?

• A. Patient A
• B. Patient B
• C. Both patients
• D. Neither patient

Answer: (B)

PSA values are measured in ng/mL, and normal levels are much lower than 100. A value above 100 ng/mL is extremely high and typically points to a substantial disease burden or, rarely, a lab error. When examining the time course, only the patient labeled as Patient B has a data point that crosses the 100 ng/mL threshold at any time; the other patient’s values never reach that level. In clinical practice, a PSA this high would prompt repeat testing to confirm and imaging to assess disease extent, since such elevations are strongly associated with advanced prostate pathology.