What finding indicates that oral rehydration therapy for a 3-year-old with dehydration has been effective?

A urine specific gravity of 1.015 indicates that the child is adequately hydrated. In the context of dehydration, normal or improved urine specific gravity is a positive sign, suggesting that the kidneys are functioning well and that the body is effectively reabsorbing fluids.

When dehydrated, a child's urine specific gravity typically increases, reflecting concentrated urine due to fluid loss. As rehydration therapy takes effect, the specific gravity should decrease as the body begins to maintain or restore fluid balance. A value of around 1.015 is close to the expected range for healthy hydration, indicating that the oral rehydration therapy is working.

In contrast, increased heart rate would suggest ongoing dehydration or stress rather than effective rehydration. Dry mucous membranes are a classic sign of dehydration and would not indicate improvement. Significant weight loss reflects dehydration severity, and if the therapy were effective, you would expect to see weight stabilization or gain.