Low urine osmolality is not necessarily kidney failure. Urine osmolality is an indicator that reflects the number of solute particles in the urine, and is often used to evaluate the concentration function of the kidneys. Low urine osmolality suggests a decrease in the concentration function of the kidneys, or dilution of urine. Low urine osmolality may be caused by physiologic or pathologic factors; physiologic factors refer to the fact that under the condition of drinking more water, the volume of urine increases, and the dilution of urine is manifested as a decrease in osmolality, which is not caused by renal disease in this case. Pathological factors are more common, and the common ones are chronic pyelonephritis, chronic nephritis and other renal diseases, which cause impaired reabsorption and concentration functions of the kidneys, and the development of these diseases is renal failure in the end, so low urine osmolality may be caused by renal failure, but it is not clear that whether it has already progressed to the stage of renal failure. Also consider uremia, which is caused by a decrease in antidiuretic hormone or renal insensitivity to antidiuretic hormone. Low urine osmolality is not necessarily kidney failure, after excluding physiological factors, it is necessary to combine with other tests such as blood creatinine, urea nitrogen, renal ultrasound and so on to further clarify. If you feel unwell, you should go to the hospital in time and consult the doctor under the guidance of the doctor.