During which phase is urine output minimal due to low GFR?

The pre-diuretic phase is characterized by minimal urine output due to a low glomerular filtration rate (GFR). This phase occurs as the kidneys are still recovering from an initial injury or insult, and the filtration processes are not yet fully functioning. During this stage, the kidneys attempt to maintain homeostasis, often resulting in fluid retention and decreased urine output.

In this phase, the body is primarily focused on stabilizing fluid balance and might not be able to efficiently filter waste products from the bloodstream. Therefore, monitoring kidney function and urine output is crucial in assessing the overall condition of the patient during this stage. As the GFR begins to improve, urine output will start to increase, moving the patient into the diuretic phase.