Pediatric reference intervals for lipids and apolipoproteins on the VITROS 5,1 FS Chemistry System

Objectives: Lipid biomarkers are integral in the assessment of dyslipidemia and cardiovascular risk, conditions that have become increasingly prevalent in pediatric populations. A comprehensive set of pediatric reference intervals for traditional or recently established lipid analytes is not currently available. Design and methods: 525 outpatient samples from a pediatric population were categorized into five age groups ranging from 0 to 20 years of age. Groups were further partitioned by gender. Serum or plasma samples were analyzed on the VITROS 5,1 FS Chemistry System for cholesterol and triglycerides by dry-film methods, direct HDL-C and LDL-C by selective detergent elimination, and apolipoproteins AI and B by immunoturbidimetry. Reference intervals were established by non-parametric methods at the 2.5th and 97.5th percentiles. Results: Lipid levels show age- and gender-related differences, particularly during the first year of life and in young adults following puberty. Concentrations of total cholesterol, LDL-C, and apo B were lowest in the 12 months after birth and remained relatively constant throughout childhood, but decreased for males in early adulthood. Triglyceride levels increased gradually throughout childhood and adolescence, and along with cholesterol, the upper limits of these intervals exceeded the recommended concentrations of lipid levels in children. For HDL-C and apo AI, no age- or sex-related differences were found until after puberty when values for males decreased slightly. Conclusions: Our current reference intervals in children and adolescents provide an important update for lipid markers and suggest earlier incidence of hypercholesterolemia when compared to previous ranges. Increased profiling of lipids is anticipated, and these will aid in the early assessment of cardiovascular risk in pediatric populations.