What does a high specific gravity indicate about urine?

A high specific gravity of urine indicates that the urine is concentrated, which is often a result of dehydration. When the body is dehydrated, it conserves water by reabsorbing more at the level of the renal tubules, leading to less water in the urine and thus a higher concentration of solutes. This concentration increases the specific gravity, reflecting the kidneys' ability to concentrate urine effectively.

In individuals with normal kidney function, a high specific gravity can suggest that the body is responding appropriately to the need to conserve water. It may be seen in situations such as prolonged exercise, fever, or inadequate fluid intake. Conversely, dilute urine, associated with a low specific gravity, signals overhydration or problems with the kidneys’ ability to concentrate urine, which does not apply in this context. Renal failure typically leads to issues with specific gravity, often resulting in a lower specific gravity due to the kidneys' compromised ability to concentrate the urine effectively.

Thus, a high specific gravity is a reliable indicator of concentrated urine, primarily resulting from dehydration.