Adams PC, Reboussin DM, Press RD, Barton JC, Acton RT, Moses GC, Leiendecker-Foster C, McLaren GD, Dawkins FW, Gordeuk VR, Lovato L, Eckfeldt JH. Biological variability of transferrin saturation and unsaturated iron-binding capacity. Am J Med. 2007 Nov; 120(11):999.e1-7.