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Pediatric reference intervals for random urine calcium, phosphorus and total protein
Patricia R Slev1, Ashley M Bunker, William E Owen
1ARUP Institute for Clinical & Experimental Pathology, Salt Lake City, UT, USA. patricia.slev@aruplab.com
Pediatric Nephrology (Berlin, Germany)
|May 18, 2010
Summary
This study established age-specific urine reference intervals for calcium, phosphorus, and total protein in children and adolescents. These new pediatric reference ranges are crucial for accurate clinical interpretation.
Area of Science:
- Clinical Chemistry
- Pediatric Nephrology
- Biomarker Research
Background:
- Establishing accurate reference intervals for urinary analytes is essential for diagnosing and monitoring pediatric kidney function and metabolic disorders.
- Existing reference ranges for calcium, phosphorus, and total protein in urine may not adequately reflect physiological changes during childhood and adolescence.
- Age- and gender-specific reference values are critical due to developmental variations in renal function and solute excretion.
Purpose of the Study:
- To determine age-appropriate reference intervals for urinary calcium (Ca), phosphorus (P), and total protein (UTP) in a pediatric population.
- To establish reference ranges normalized to creatinine (Cr) to account for urine dilution variations.
- To provide gender- and age-stratified reference intervals for improved clinical utility in children aged 7 to 17 years.
Main Methods:
- Analyzed random urine samples from 674 boys and 728 girls aged 7–17 years.
- Measured urinary Ca, P, and UTP using the Roche MODULAR P analyzer, with results normalized to urinary creatinine (Cr).
- Employed non-parametric analysis to determine central 95% reference intervals with 90% confidence intervals, partitioned by gender and 2-year age groups.
Main Results:
- Established distinct upper reference limits for Ca/Cr, P/Cr, and UTP/Cr, varying significantly with age and gender.
- Observed a general trend of decreasing upper reference limits for all analytes as age increased.
- Age was identified as a statistically significant factor influencing all measured urinary analytes, necessitating age-specific intervals.
Conclusions:
- Proposed eight unique age- and gender-specific reference intervals for urinary Ca/Cr, P/Cr, and UTP in pediatric populations.
- These findings provide crucial updated reference data for the accurate assessment of mineral and protein excretion in children and adolescents.
- The established intervals will aid clinicians in the precise interpretation of urine tests for pediatric kidney and metabolic health.
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