Reference serum creatinine levels determined by an enzymatic method in Japanese children: relationship to body length

Area of Science:

• Pediatric Nephrology
• Clinical Chemistry

Background:

• Standard serum creatinine (Cr) values are crucial for pediatric chronic kidney disease (CKD) care.
• The traditional Schwartz formula for estimated glomerular filtration rate (eGFR) uses the Jaffe method for Cr measurement.
• The shift to enzymatic Cr assays necessitates reevaluating the kappa coefficient in the eGFR equation.

Purpose of the Study:

• To establish standard serum creatinine (Cr) values for pediatric chronic kidney disease (CKD) patients using enzymatic methods.
• To reevaluate the coefficient kappa in the estimated glomerular filtration rate (eGFR) equation due to the prevalence of enzymatic Cr assays.
• To develop a new formula for estimating normal serum Cr levels based on body length.

Main Methods:

• Serum Cr levels were measured using an enzymatic method in healthy children.
• Linear regression analysis was employed to determine the relationship between body length and serum Cr levels.
• A regression equation was derived to estimate reference serum Cr values from body length.

Main Results:

• A regression equation was established for estimating reference serum Cr values based on body length.
• For children aged 1-12 years, the formula: body length (m) x 0.30 approximates the reference serum Cr level.
• This finding provides a method for assessing normal serum Cr in pediatric populations.

Conclusions:

• This study reports the determination of reference serum Cr levels using enzymatic methods in Japanese children for the first time.
• The developed formula, serum Cr (mg/dl) = 0.30 x body length (m), is proposed for screening renal function in Japanese children.
• The findings support the use of enzymatic methods and a length-based formula for pediatric renal function assessment.