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Pediatric reference intervals for 19 biologic variables in healthy children
M F Burritt1, J M Slockbower, R W Forsman
1Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN 55905.
Insights
This study establishes age- and sex-specific reference intervals for 19 serum biologic variables in children aged 1-22 years. These findings provide crucial pediatric reference ranges for common laboratory tests.
Area of Science:
- Clinical Chemistry
- Pediatric Laboratory Medicine
- Biostatistics
Background:
- Establishing accurate reference intervals is crucial for interpreting pediatric laboratory test results.
- Existing reference intervals may not adequately account for age and sex variations in children.
- Common laboratory equipment was utilized to ensure broad applicability.
Purpose of the Study:
- To define age- and sex-specific reference intervals for 19 biologic variables in serum from healthy children.
- To provide updated and precise reference ranges for pediatric clinical chemistry.
- To identify trends and differences in biologic variables across pediatric age groups and sexes.
Main Methods:
- Serum samples from healthy children aged 1 to 22 years were analyzed.
- Age- and sex-specific reference intervals were determined using polynomial regression for age-dependent variables.
- Parametric and nonparametric percentile methods (2.5th and 97.5th) were employed to define intervals.
Main Results:
- No significant age or sex differences were observed for sodium, total protein, glucose, direct bilirubin, and albumin.
- Potassium, chloride, and urea levels showed age-independent differences compared to adults.
- Creatinine, uric acid, bicarbonate, and immunoglobulins demonstrated age-related trends, with some sex-specific variations noted for certain analytes.
Conclusions:
- This study provides comprehensive, age- and sex-specific reference intervals for 19 serum biologic variables in children.
- The findings highlight significant age-related changes in several pediatric serum analytes.
- These established intervals are vital for accurate diagnosis and monitoring in pediatric healthcare.
Abstract:
We defined age- and sex-specific reference intervals for 19 biologic variables in serum samples from healthy children, 1 to 22 years of age, using common laboratory equipment. Upper and lower reference intervals were defined as the estimated 2.5 and 97.5 percentiles of the distribution. For variables (y) that varied with age, the relationship of y to age was modeled with polynomial regression. Parametric percentile estimates specific to each age were then calculated as the predicted y value +/- 1.96 . SD, in which SD = the standard deviation of the residuals. For variables not associated with age, the nonparametric 2.5 and 97.5 sample percentiles were used to define the reference intervals. No significant age or sex differences were found for serum sodium, total protein, glucose, direct bilirubin, or albumin. Potassium, chloride, and urea showed constant values in children that were higher than adult values in the case of potassium and chloride and lower than adult values in the case of urea. No sex-related differences were seen for these analytes. Creatinine, uric acid, and bicarbonate showed an upward trend in values with increasing age, whereas aspartate aminotransferase, phosphorus, and total and ionized calcium showed a downward trend with increasing age. Sex-related differences were noted for these analytes. The immunoglobulins (IgG, IgA, and IgM) showed an upward trend with increasing age, with no sex-related differences except for IgM in children.