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Reference intervals for serum cystatin C in Brazilian children aged 5-11 years: A short report

Natalia Flores Jacobi1,2, Ana Carolina Marques Ciceri1,2, Laura Eduarda de Oliveira1,2

  • 1Graduate Program in Pharmaceutical Sciences, Federal University of Santa Maria, Santa Maria, Brazil.

Annals of Clinical Biochemistry
|November 17, 2025
PubMed

Insights

This study established reference intervals for serum Cystatin C (CysC), a kidney function biomarker, in healthy Brazilian children aged 5-11 years. The findings provide crucial data for accurate pediatric clinical assessments.

Area of Science:

  • Pediatric Nephrology
  • Clinical Biochemistry
  • Biomarker Research

Background:

  • Cystatin C (CysC) is a key biomarker for assessing kidney function.
  • Serum CysC levels are sensitive to kidney injury and influenced by geographic and ethnic factors.
  • Establishing regional reference intervals (RIs) is essential for accurate clinical interpretation.

Purpose of the Study:

  • To determine reference intervals (RIs) for serum Cystatin C (CysC) in healthy children.
  • To establish age- and sex-specific RIs for pediatric populations in Southern Brazil.
  • To support accurate clinical decision-making regarding kidney function in children.

Main Methods:

  • Enrolled 134 healthy children aged 5-11 years from public schools in Santa Maria, Brazil.
  • Measured serum Cystatin C levels using immunoturbidimetry.
  • Defined reference intervals using the 2.5th and 97.5th percentiles.

Main Results:

  • The overall reference interval for serum CysC was 0.59-1.10 mg/L.
  • Sex-specific RIs were 0.53-1.10 mg/L for females and 0.61-1.10 mg/L for males.
  • These RIs are specific to the studied pediatric population in Southern Brazil.

Conclusions:

  • The study provides the first CysC reference intervals for healthy children in Southern Brazil.
  • These findings are vital for improving the clinical utility of CysC in pediatric nephrology.
  • Further research is recommended to validate and refine CysC's application in pediatrics.

Keywords:
Childrencystatin Creference intervalsrenal biomarker

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