Normal values for pediatric urinary biochemistry in early infancy.

Area of Science:

• Pediatric Nephrology
• Biochemical Markers
• Renal Physiology

Background:

• Urinary N-acetyl-β-D-glucosaminidase (NAG), α1-microglobulin (α1-MG), and β2-microglobulin (β2-MG) are established markers for renal tubular damage.
• Previous studies determined normal values for these markers in healthy children over 3 years old.
• Normal values for infants and children under 2 years old were unclear, with very high levels observed in those under 1 year.

Purpose of the Study:

• To determine normal urinary biochemical marker values in children under 2 years old.
• To establish reference ranges for NAG, α1-MG, and β2-MG in this pediatric population.
• To identify reliable urinary markers for assessing renal tubular function in early childhood.

Main Methods:

• Collected fresh urine samples from 293 healthy children (newborns to 2-year-olds).
• Performed standard urinalysis on all samples.
• Measured urinary levels of NAG, α1-MG, β2-MG, and creatinine (Cr) immediately in a central laboratory.

Main Results:

• Established normal reference values for urinary NAG, α1-MG, and β2-MG in children under 2 years of age.
• Observed that urinary α1-MG levels decrease most rapidly with age, nearing levels seen in children ≥3 years by 6 months of age.
• Creatinine (Cr) levels were also measured for normalization.

Conclusions:

• The determined normal values allow for the evaluation of renal tubular function in children under 3 years old.
• Urinary α1-MG appears to be the most stable and useful marker for assessing renal health from early infancy.
• This study provides crucial reference data for pediatric nephrology and clinical diagnostics.