Pediatric-specific reference intervals in a nationally representative sample of Iranian children and adolescents: the CASPIAN-III study

Reference ranges for select elements and metals in healthy biomatrices

INTRODUCTION/OBJECTIVE

This review aimed to consolidate and compare reference values (RVs) for various elements and metals in biological samples from healthy populations worldwide.

METHODS

A Web of Science/PubMed/Scopus review was conducted. Original articles in the English language, from January 2012 to February 2022, with at least 120 participants and 3 evaluated elements, and biological samples of whole blood, serum, plasma, umbilical cord, and hair included in this review.

RESULTS

Ninety-nine studies were screened and assessed, and eventually, 29 eligible studies from 15 countries and a total recruitment of 26,676 healthy subjects, ages ranging from zero to 80 years were included in this review. The results of evaluating 36 trace/micro/meso/macro/ toxic metals and elements in biological fluids and hair were extracted from eligible studies. Several indicators include reference range (lower, upper), arithmetic and geometric mean, median, percentile (lower, upper), and confidence interval (CI) 95 % of evaluated elements were reported. Due to geographical conditions, different demographic factors, and different analytical methodologies, the results of the analysis were various in different countries.

CONCLUSIONS

This review points out the necessity for localized RVs and standardized methodologies for accurate clinical evaluations and bio-monitoring. The findings call for extensive studies across diverse populations to develop comprehensive RVs for elements and metals, ensuring effective health assessments and environmental exposure controls.

Plasma lipids paediatric reference intervals: Indirect estimation using a large 14-year database

OBJECTIVES

Establishing direct reference intervals (RIs) for paediatric patients is a very challenging endeavour. Indirect RIs can address this problem, using existing clinical laboratory databases from real-world data research. Compared to the traditional direct method, the indirect approach is highly practical, widely applicable, and low-cost. Considering the relevance of dyslipidemia in the paediatric age, to provide better laboratory services to the local paediatric population, we established population-specific lipid RIs via data mining.

METHODS

Our laboratory information system was searched for cholesterol (TC), triglycerides (TG), low-density lipoprotein (LDL) and high-density lipoprotein (HDL) of patients aged less than 18 years, performed from January 2009 until December 2022. RIs were estimated using RefineR algorithm.

RESULTS

Values from 215,594 patients were initially collected. After refining data on the basis of specific exclusion criteria that left 17,933 patients, we determined the RIs for each analyte, including corresponding 95% confidence interval (95% CI). Age and sex partitions were required for proper stratification of the heterogenous subpopulations. Age-related variations in TC and TG values were observed mainly in children until 5 years. RIs were defined for children less than 3 years and for those of 3-18 years. In our population, the obtained RIs were comparable with those of the literature, but the upper TG limit in subjects under the age of 3 (2.03 mmol/L with 95% CI: 1.45-2.86) was lower than that previously reported.

CONCLUSIONS

Our RIs, necessary for paediatric lipid monitoring, are tailored to the serviced patient population as should be done whenever possible.

The distributions of hematologic and biochemical values in healthy high-school adolescents in Japan

Laboratory tests of adolescents are often interpreted by using reference intervals derived from adults, even though these populations differ in their physical and physiologic characteristics and disease susceptibility. Therefore, to examine the distribution of laboratory values specific for adolescents, we analyzed hematologic and biochemical measurements obtained from 12,023 healthy Japanese adolescents (ages 15 through 18 years; male, 9165; female, 2858) during 2009 through 2018. Distributions were shown as medians with 95% (2.5th and 97.5th percentiles) of values and were compared with those from previous studies that examined similar Asian populations. There were some differences between hematologic parameters, serum creatinine and uric acid concentration, and lipid levels of Japanese adults and adolescents. In comparison with other Asian populations, the distributions of serum uric acid and high-density-lipoprotein cholesterol in the present study were slightly higher than those in the other studies. Although further research is need, the distributions of hematologic and biochemical tests in adolescents may have the potential to facilitate the early identification and management of disease in this population.

Clinical thresholds for diagnosing iron deficiency: comparison of functional assessment of serum ferritin to population based centiles

Low serum ferritin is diagnostic of iron deficiency, yet its published lower cut-off values are highly variable, particularly for pediatric populations. Lower cut-off values are commonly reported as 2.5th percentiles, and is based on the variation of ferritin values in the population. Our objective was to determine whether a functional approach based on iron deficient erythropoiesis could provide a better alternative. Utilizing 64,443 ferritin test results from pediatric electronic health records, we conducted various statistical techniques to derive 2.5th percentiles, and also derived functional reference limits through the association between ferritin and erythrocyte parameters: hemoglobin, mean corpuscular volume, mean cell hemoglobin concentration, and red cell distribution width. We find that lower limits of reference intervals derived as centiles are too low for clinical interpretation. Functional limits indicate iron deficiency anemia starts to occur when ferritin levels reach 10 µg/L, and are largely similar between genders and age groups. In comparison, centiles (2.5%) presented with lower limits overall, with varying levels depending on age and gender. Functionally-derived limits better reflects the underlying physiology of a patient, and may provide a basis for deriving a threshold related to treatment of iron deficiency and any other biomarker with functional outcomes.

Age-specific and sex-specific reference intervals for non-fasting lipids and apolipoproteins in 7260 healthy Chinese children and adolescents measured with an Olympus AU5400 analyser: a cross-sectional study

AIMS

Ethnic, demographic, lifestyle, genetic and environmental factors influence lipids and apolipoproteins. The aim of this study was to establish age-specific and gender-specific reference intervals for non-fasting lipids and apolipoproteins in healthy Chinese children and adolescents.

METHODS

This study followed the Clinical and Laboratory Standards Institute EP28-A3c guidelines. Non-fasting samples were collected from 7260 healthy Chinese children and adolescents, and they were analysed using the Olympus AU5400 analyser for: triglycerides, total cholesterol (TC), high-density lipoprotein cholesterol, low-density lipoprotein cholesterol (LDL-C), apolipoprotein A1 and apolipoprotein B (ApoB). The age-related and gender-related reference intervals were partitioned using the Harris-Boyd method. The non-parametric method was used to establish the lower limit (2.5th percentile) and the upper limit (97.5th percentile) for the reference intervals. The 90% CIs for the lower and upper limits were also calculated.

RESULTS

Based on the Harris-Boyd method, gender partitions were required for TC, LDL-C and ApoB. Age differences were observed for all analytes. Paediatric reference intervals were established for non-fasting lipids and apolipoproteins based on a large population of healthy children and adolescents.

CONCLUSIONS

Previously used reference intervals did not take age and gender into account. These age-specific and gender-specific reference intervals established in this study may contribute to improved management and assessment of paediatric diseases.

Prevalence of Vitamin D Deficiency and Calcium Homeostasis in Saudi Children

OBJECTIVE

Vitamin D deficiency (VDD) and vitamin D insufficiency (VDI) are significant health problems all over the world. The aim of this study was to determine the prevalence of VDD and VDI in children and adolescents residing in 8 provinces in the Kingdom of Saudi Arabia and to also investigate calcium homeostasis in these subjects.

METHODS

A cross-sectional study was conducted in 2110 participants aged between 6 and 15 years. Information on socio-demographic status, anthropometric measurements, knowledge about vitamin D, color of the skin, dietary intake, sun exposure experience, smoking, and physical activity were collected through a questionnaire given to the parents of all subjects. The subjects were divided into three groups as vitamin D deficient, vitamin D insufficient, and vitamin sufficient according to their blood level of vitamin D [VDD ≤25 nmol/L (25 hydroxy vitamin D), VDI >25-50 nmol/L, and VDS >50 nmol/L].

RESULTS

VDD was highly prevalent in this group of children. 95.3 of the subjects had either VDD (45.5%) or VDI (49.9%). The prevalence rate of VDD combined with VDI was higher in females (97.8%) compared to males (92.8%) (p<0.001). Only 1.6% had significant hypocalcaemia. Children with dark skin had lower concentrations of vitamin D and higher concentrations of parathormone. A positive correlation was observed between 25 hydroxy vitamin D level and serum calcium, inorganic phosphate, and alkaline phosphatase concentrations. onclusion: The results showed a high prevalence of VDD and VDI in Saudi children with significantly higher prevalence in girls. These findings necessitate the set-up of a national program for vitamin D supplementation and health education for this vulnerable group.