Quantification of proteinuria with urinary protein to osmolality ratios in children with and without renal...

Area of Science:

• Pediatric Nephrology
• Clinical Chemistry
• Diagnostic Biomarkers

Background:

• Spot urine analysis is recommended for proteinuria assessment but can be affected by hydration status and creatinine variability in newborns.
• The study addresses the need for validated methods to assess proteinuria in pediatric populations, considering varying renal function.

Purpose of the Study:

• To evaluate the validity of the urine protein to osmolality (Uprot/Uosm) ratio compared to the urine protein to creatinine (Up/Ucr) ratio for assessing proteinuria in children.
• To determine the correlation of these ratios with 24-hour urinary protein excretion in healthy children and those with renal insufficiency.

Main Methods:

• A comparative study involving three groups of children: normal renal function without proteinuria, normal renal function with proteinuria, and renal insufficiency.
• Analysis of early morning spot urine and 24-hour urine collections for protein, creatinine, and osmolality.
• Correlation analysis and Receiver Operating Characteristic (ROC) curve comparison between Uprot/Uosm and Up/Ucr ratios against 24-hour protein excretion.

Main Results:

• Optimal cutoff values for Uprot/Uosm were established for abnormal proteinuria (0.33 mg/L/mosm/kg H2O) and nephrotic range proteinuria (1.75 mg/L/mosm/kg H2O).
• ROC curve analysis showed no significant difference between Uprot/Uosm and Up/Ucr ratios in detecting proteinuria across different renal function groups (P>0.05).

Conclusions:

• Both Uprot/Uosm and Up/Ucr ratios derived from random urine specimens are effective predictors of 24-hour urinary total protein excretion in children.
• These ratios offer a valid alternative to 24-hour urine collection for proteinuria assessment in pediatric patients, regardless of renal status.