Establishment of reference intervals for von Willebrand factor antigen and eight coagulation factors in a Korean population following the Clinical and Laboratory Standards Institute guidelines.

Establishment of reference intervals for coagulation molecules is important but is costly and sometimes not feasible. Since reference intervals from manufacturers or the literature are mostly out of date or involved Western populations, the authors determined reference intervals for VWF: Ag and eight factors in a Korean population. VWF: Ag, factor VIII (FVIII), FII, FV, FVII, FIX, FX, FXI, and FXII were determined in Korean individuals visiting for routine checkup following the CLSI (Clinical and Laboratory Standards Institute) guidelines. Reagents by Diagnostica Stago were used on the STA Compact Analyzer (Diagnostica Stago). Exclusion criteria were medical history or laboratory findings that could affect the factor levels. Influence of demographic factors was analyzed. Mean ± 2 × SD or central 95 percentile was used, as appropriate. We obtained data from 266 adults for VWF: Ag, 371 adults for FVIII, and minimum 136 adults for the rest. Reference interval for VWF was 51–176% (52–155% in blood group O and 71–186% for non-O). Reference interval for FVIII was 64–197% (55–150% in O and 77–205% in non-O). Reference interval for FII was 77–121%, FV 81–160%, FVII 68–149%, FIX 67–154%, FX 69–126%, FXI 59–138%, and FXII 48–177%. The medians of VWF: Ag, FVIII, and FIX were significantly higher in the elderly group (≥60 years). We established local reference intervals for VWF: Ag and eight coagulation factors in a Korean population according to the CLSI guidelines. Significantly, different reference intervals were obtained in blood group O vs. non-O for VWF: Ag and FVIII. The reference intervals obtained in this study could be adopted in other clinical laboratories after appropriate validation.