What is urine osmolality?

Osmotic pressure in urine is often seen in too little drinking water, or water loss caused by various reasons, urine shows concentration and causes osmotic pressure increase, so increase drinking water or correct water loss, osmotic pressure can return to normal. Osmotic pressure in urine is an indicator reflecting the amount of osmotic active ions in urine, and is an ideal indicator for evaluating kidney concentration function. Urine osmolality is generally 600-1000mOsm/kg·H20, and the maximum range within 24 hours is 40-1400mOsm/kg·H20. Plasma osmolality is about 275-305mOsm/kg·H20, and the ratio of urine to plasma osmolality should be 3.4-4.7: 1. Abstain water for 12 hours, urine osmolality is>800mOsm/kg·H20. If it is lower than this value, it indicates that the renal concentration function is incomplete. After 12 hours of water deprivation in normal people, the ratio of urine osmolality to plasma osmolality should be greater than 3. In acute renal tubular dysfunction, the ratio of urine osmolality to plasma osmolality should be less than 1.2.