The 24-hour urinary creatinine test is a key part of evaluating kidney function and is often used to calculate Creatinine Clearance, which estimates the Glomerular Filtration Rate (GFR). Here are short notes on 24-hour urinary creatinine:
Purpose of the Test Assess Kidney Function: Creatinine is a waste product from muscle breakdown, produced at a relatively constant rate. Healthy kidneys filter it out of the blood into the urine.
Creatinine Clearance Calculation: The main use is to calculate the Creatinine Clearance by comparing the amount of creatinine in the 24-hour urine sample with the creatinine level in a simultaneous blood sample.
This estimates how well the kidneys are filtering waste (GFR).
Check Completeness of Collection: The total amount of creatinine excreted in 24 hours can be used as a marker to verify that a patient collected all of their urine during the 24-hour period, as daily creatinine production is stable.
Evaluate Proteinuria: It is often used to calculate the Urine Protein-to-Creatinine Ratio (UPCR) or Urine Albumin-to-Creatinine Ratio (UACR) to screen for kidney damage (proteinuria).