What is the primary characteristic of renal failure?

The primary characteristic of renal failure is the inability to excrete wastes and maintain fluid balance. In renal failure, the kidneys lose their ability to filter and remove toxic substances from the bloodstream, leading to a buildup of waste products such as urea and creatinine. Additionally, the kidneys struggle to regulate fluid and electrolyte balance, which can result in issues like fluid overload, hypertension, and electrolyte imbalances.

This dysfunction can manifest as increased levels of waste products in the blood, a decrease in urine output (oliguria or anuria), and other signs of fluid retention. Understanding this core aspect of renal failure is crucial for recognizing the condition and its implications on overall health and treatment approaches.