What lab finding is associated with dehydration?

What lab finding is associated with dehydration?

• A. Elevated BUN and creatinine
• B. Low cholesterol
• C. High potassium
• D. Decreased glucose

Answer: (A)

When you're dehydrated, the circulating blood volume drops, which lowers renal perfusion and the glomerular filtration rate. In response, the kidneys conserve water and also reabsorb more urea (BUN) from the tubules. This causes BUN to rise more than creatinine, so the BUN/creatinine ratio increases—often above 20:1. This pattern—elevated BUN with a relatively elevated creatinine and a high BUN/creatinine ratio—is a classic sign of dehydration and prerenal azotemia. Other options don’t fit dehydration as reliably: cholesterol isn’t directly tied to hydration status; potassium can be influenced by many factors (acid-base balance, renal function) and isn’t a specific dehydration marker; glucose can vary with many conditions and is not a dehydration-specific lab finding.

When you're dehydrated, the circulating blood volume drops, which lowers renal perfusion and the glomerular filtration rate. In response, the kidneys conserve water and also reabsorb more urea (BUN) from the tubules. This causes BUN to rise more than creatinine, so the BUN/creatinine ratio increases—often above 20:1. This pattern—elevated BUN with a relatively elevated creatinine and a high BUN/creatinine ratio—is a classic sign of dehydration and prerenal azotemia.

Other options don’t fit dehydration as reliably: cholesterol isn’t directly tied to hydration status; potassium can be influenced by many factors (acid-base balance, renal function) and isn’t a specific dehydration marker; glucose can vary with many conditions and is not a dehydration-specific lab finding.