Time course of iron parameters. Given are mean value and standard errors for serum concentration of transferrin saturation (in %), ferritin (in μg/L) and soluble transferrin receptor (in mg/L) and for soluble transferrin receptor/ log ferritin ratio during the course of the observation period. FCM day 1 refers to day of first FCM administration, but blood for assessment of laboratory parameters was drawn before FCM administration. This is referred to as baseline (unless values from this day were missing, in which cases Pre-FCM values were used). Additional FCM doses may have been administered after this to achieve iron repletion. Weeks 0–2 comprise days 1 to 14 and weeks 2–4 comprise days 15 to 28.