Why in a healthy person does no glucose in collecting duct?

In a healthy person, glucose is typically reabsorbed in the proximal convoluted tubule of the nephron, where nearly all filtered glucose is absorbed back into the bloodstream. By the time the filtrate reaches the collecting duct, glucose levels should be negligible, as the renal threshold for glucose reabsorption is usually met. Therefore, under normal conditions, no glucose is found in the collecting duct because it has already been efficiently reabsorbed earlier in the nephron. If glucose is present in the collecting duct, it may indicate conditions like Diabetes mellitus, where glucose reabsorption is impaired.