What is "isosthenuria"

n. The excretion of urine whose specific gravity (concentration) is neither greater nor less than that of protein-free plasma.

Isosthenuria refers to the excretion of urine whose specific gravity (concentration) is neither greater (more concentrated) nor less (more dilute) than that of protein-free plasma, typically 1.008-1.012. Isosthenuria reflects renal tubular damage/failure of renal medullary function.

A closely related term is hyposthenuria, where the urine has a relatively low specific gravity, though not necessarily equal to that of plasma. Therefore, unlike isosthenuria, this condition is not associated with renal failure as the kidney tubules have altered the glomerular filtrate