TABLE 2

Age-Related Reference Ranges for Antithrombin, TFPI, Thrombin, and Xa

Day 1Day 31 mo to 1 y1–5 y6–10 y11–16 yAdult
Factor II, %54 (41–69)a62 (50–73)a90 (62–103)a89 (70–109)a89 (67–110)a90 (61–107)a110 (78–138)
Factor X, %55 (46–67)a60 (46–75)a95 (77–122)a98 (72–125)a97 (68–125)a91 (53–122)a124 (96–171)
Total TFPI, ng/mLNANA77.49 (69.42–85.58)76.33 (61.27–89.80)73.99 (59.13–88.02)a74.09 (61.63–87.36)87.49 (63.64–104.38)
Antithrombin, %76 (58–90)a74 (60–89)a109 (72–134)a116 (101–131)a114 (95–134)a111 (96–126)a96 (66–124)
Endogenous Thrombin Potential, pM·minNANA4865 (2653–7162)4429 (2537–6084)5363 (2719–8938)7593 (3373–7516)8475 (7043–10205)
  • Each row shows mean and boundaries (95% of population). Adapted with permission from Monagle P, Barnes C, Ignjatovic V, et al. Thromb Haemost. 2006;95(2):362–372.

  • a Values significantly different from those in the adult reference range.