Abstract
BACKGROUND AND AIMS: Children's coagulation system undergoes dynamic changes during development, necessitating age-specific reference intervals (RIs). This study aimed to establish RIs for 16 coagulation parameters in Chinese children aged 0-18 years using the Sysmex CN-6000 analyzer. METHODS: We conducted a cross-sectional study in children aged 0 day to 18 years who met the inclusion and exclusion criteria. Participants were stratified into six age groups (0-30 days, 1-6 months, 6-12 months, 1-3 years, 3-12 years, and 12-18 years) and blood samples were collected. Routine parameters (APTT, PT, PT-INR, TT, Fibrinogen [Fib]), thrombotic markers (AT-III, D-Dimer [D-Di], Fibrin Degradation Products [FDP]), and coagulation factors (II, V, VII, VIII, IX, X, XI, XII) were analyzed using the Sysmex CN-6000 analyzer. RIs and their 90% confidence intervals (CIs) were calculated using the non-parametric method (for n ≥ 120) or the robust method (for n < 120). RESULTS: Neonates exhibited distinct coagulation profiles, including prolonged APTT (22.7 s-46.5 s) and TT (16.2 s-20.8 s), reduced levels of anticoagulant and coagulation factors (e.g., AT-III: 23.1%-91.3%, factor II: 26.5%-77.5%), and elevated fibrinolytic markers (D-Di ≤ 1.41 μg/mL; FDP ≤ 4.44 μg/mL). Age-dependent trends were evident: APTT shortened until adolescence (24.7 s-32.9 s), while factor IX increased progressively (16.3% - 43.2% in neonates vs. 43.6%-108.6% in adolescents). Novel RIs for neonatal D-Di and FDP were established, addressing a critical gap in developmental hemostasis. Sex-specific differences in TT were observed but deemed clinically insignificant. CONCLUSION: Age-specific RIs are essential for children. This study provides the first comprehensive RIs for Sysmex CN-6000 in Chinese children, aiding in the diagnosis and management of coagulation disorders in pediatrics.