Abstract
Coagulation parameters are critical for the diagnosis and management of bleeding disorders, yet existing reference intervals (RIs) often neglect demographic variations. This study established sex- and age-specific RIs for six coagulation parameters, including lupus anticoagulant (LA) ratio, protein C/S (PC/PS) activity, factor VIII/IX (FVIII/FIX) activity, and von Willebrand factor antigen (vWF Ag), in healthy Chinese adults from Shenzhen and Beijing. Coagulation parameter distributions were explored using kernel density plots and boxplots, with statistical comparisons across sex or age groups. Based on clinical considerations, sex- and age-specific 95% RIs were established for each parameter. Following data screening, males showed higher LA ratios and PS activity. Additionally, PC, FVIII, and vWF Ag increased progressively with age, while FIX remained unaffected. Consequently, sex-specific RI were defined for PS, while age-specific RIs were established for FVIII and vWF Ag. LA ratios retained uniform cutoffs despite sex differences. PC activity exhibited only slight variations in lower reference limits across age groups. Given that clinical practice primarily emphasizes deficiency screening, age-specific stratification for PC was considered unnecessary. These results highlight the necessity of establishing population-specific RIs that account for demographic variations, thereby enhancing diagnostic accuracy and clinical decision-making in local population.