Normal filtration fraction is around:
High-Yield Explanation
The ratio of the GFR to the RPF, the filtration fraction, is normally 0.16 to 0.20. The GFR varies less than the RPF. When there is a fall in systemic blood pressure, the GFR falls less than the RPF because of efferent aeriolar constriction, and consequently the filtration fraction rises. Ref: Ganong's Review of Medical Physiology 23rd edition, Chapter 38.