total urine output per day from spot urine analysis

Q: How total urine output per day can be estimated from spot urine analysis?

Answer: It can easily be calculated by the following formula

 Estimated daily urine output  =  100  ÷  Urine creatinine concentration (mg/dL)

This formula is applicable only if patient has stable glomerular filtration rate (GRF). Creatinine concentration can be obtained from a spot urine sample.

#nephrology

Reference:

Dong Y, Silver SM, Sterns RH. Estimating urine volume from the urine creatinine concentration. Nephrol Dial Transplant. 2023 Mar 31;38(4):811-818. doi: 10.1093/ndt/gfab337. PMID: 34850163.