What does a high urine specific gravity typically indicate?

• A. Dilute urine due to overhydration.
• B. Kidney failure with protein loss.
• C. Concentrated urine due to dehydration or concentrating ability.
• D. Glucosuria.

Answer: (C)

Urine specific gravity shows how concentrated or dilute the urine is by measuring its solute density relative to water. A high value means the urine is concentrated, with more solutes in a smaller amount of water.

This concentration typically happens when the body is conserving water, such as during dehydration. In dehydration, antidiuretic hormone promotes water reabsorption in the kidneys, so urine becomes more concentrated and its specific gravity rises. That’s why a high reading points to concentrated urine from dehydration or from the kidneys’ ability to concentrate urine when needed.

Dilute urine from overhydration would lower the specific gravity, and kidney failure that impairs concentrating ability often leads to less concentrated urine rather than more, so it wouldn’t explain a high reading. Glucosuria can elevate specific gravity due to osmotic effects, but the common interpretation centers on dehydration and the kidney’s concentrating function.