LAUSR

This study aimed to explore the consistency of insulin-like growth factor-1 (IGF-1) and insulin-like growth factor-binding protein-3 (IGFBP-3) by detecting peripheral whole blood and venous serum among children. As a cross-sectional study, children who were aged 0-14 as well as received physical examinations in the Child Healthcare Department of the Children's Hospital of Nanjing Medical University during January 2022 to April 2022 were enrolled in this study. Meanwhile, both of peripheral whole blood and venous serum samples were collected, and the levels of IGF-1 and IGFBP-3 were assayed individually via chemiluminescence immunoassay (CLIA). Additionally, linear regression equation was used to analyze the correlation of results between two categories of samples, while Inter-class Correlation Coefficient (ICC) was used to evaluate the consistency of test results among two types of samples. The change trends of IGF-1 and IGFBP-3 with age were analyzed at the same time. A total of 203 valid matched samples were collected, including 117 boys and 86 girls. Peripheral whole blood was well correlated with serum IGF-1 (r=0.986, P<0.001) and IGFBP-3 (r=0.974, P<0.001), and the linear regression equation is shown as follows: (IGF-1) venous serum =1.047×(IGF-1) peripheral whole blood-6.840; (IGFBP-3) venous serum=0.924×(IGFBP-3) peripheral whole blood+0.396. The correlation and consistency were still persisted after being stratified by sex and age. ICC of IGF-1 and IGFBP-3 were 0.983 and 0.967, respectively which provided an excellent strength of agreement. The levels of IGF-1 or IGFBP-3 in boys' and girls' peripheral whole blood and serum showed significant statistical differences among various age groups (all P<0.001), and also increased significantly with age (all P trend<0.001). In conclusion, the results of IGF-1 and IGFBP-3 in peripheral whole blood and venous serum had positive comparability that could be mutually recognized. The detection of IGF-1 and IGFBP-3 in peripheral whole blood had great potential for young age children by providing guidance for nutritional intervention, growth and development assessment.