It sounds like a simple 24 hr urine sodium test may be an easy marker for hypovolemia...I recently tested mine and it came back <20. "With hypovolemia, the urine sodium typically measures less than 25 mEq/L." https://emedicine.medscape.com/article/242166-workup?src=soc_fb_share According to this article, "A 24-hour urine sodium is a simple and helpful test that provides documentation that the patient is taking sufficient fluids and sodium. The goal is a volume of 1,500– 2,500 mL and sodium excretion of 170 mmol/24 hours." Anyone else ever done a urine sodium?