Which parameter is most useful for assessing hydration status in an ill patient?

• A. Skin turgor
• B. Blood pressure
• C. Heart rate
• D. Weight change and mucous membrane moisture

Answer: (D)

Hydration status is best gauged by tracking actual fluid balance over time, which is most directly reflected by weight changes and the moisture of mucous membranes. Daily or regular weighing shows net fluid gain or loss—the simplest way to quantify dehydration or overhydration—especially when you compare to a stable baseline and use the same scale and conditions. Mucous membrane moisture gives a quick tissue-level read on circulating volume: dry or tacky membranes and reduced moisture suggest dehydration and poorer perfusion.

Other signs are less reliable when used alone. Skin turgor can be misleading in many patients (older animals, those with obesity or edema, or skin diseases). Blood pressure may stay normal until late in dehydration and is influenced by many other factors; heart rate can rise for reasons other than dehydration, such as pain or fever. Together, weight change and mucous membrane moisture provide a more accurate, practical assessment of hydration status in an ill patient, and they allow tracking of trends as treatment progresses.