What is implied if a drug has more clearance than the GFR?
Drug is reabsorbed in the tubules
Drug is secreted in the tubules
Drug is excreted in bile
Drug is neither secreted nor reabsorbed
The clearance of the substance equals the GFR if there is no net tubular secretion or reabsorption (Inulin), exceeds the GFR if there is net tubular secretion (PAH), and is less than the GFR if there is net tubular reabsorption (Glucose). Ref: Ganong 25th ed/page 679
Renal physiology