Post-renal biopsy, which symptom is most closely associated with complications that need immediate assessment?

Bleeding from the biopsy site is a critical symptom that warrants immediate assessment following a renal biopsy procedure. This is because renal biopsies can lead to complications such as hematoma formation or significant bleeding, which may indicate a serious issue like vascular injury or an underlying coagulopathy. Monitoring for bleeding is essential, as it can lead to further complications such as hypotension or shock if not addressed promptly.

In contrast, increased appetite or stiffness in the lower back may not signal acute complications requiring urgent intervention. Abdominal discomfort can also arise post-procedure but does not necessarily indicate a severe or life-threatening situation as directly as bleeding does. Thus, the presence of bleeding from the biopsy site stands out as the most critical symptom needing immediate attention in this scenario.