Table 2.

Storage iron turnover rate(SIT) and SIT-related indices estimated in the model of a typical normal male with 70 kg body weight, 2400 mg red cell iron at 15 g/dl hemoglobin and 4800 ml blood volume, 120 day mean red cell life span, 80% red cell radioiron utilization (RCU), and 30 mg/day plasma iron turnover rate (PIT)

(cf. Table 3 and Fig. 7)

RCIT; red cell iron turnover rate: PIT × RCU/100	30 × 0.8 = 24 mg/day
RCIR; red cell iron renewal rate: (red cell iron/mean red cell life span)	2400/120 = 20 mg/day
PTIT; parenchymal tissue iron turnover rate: (PIT – RCIR)	30 – 20 = 10 mg/day
SIT; storage iron turnover rate: (PIT – RCIR) × 0.7*	10 × 0.7 = 7 mg/day
PTIT due to tissue-fixed radioiron: PIT × (1 – RCU/100) = PIT × 0.2	30 × 0.2 = 6 mg/day
SIT due to storage-fixed radioiron (SITf): (PIT – RCIT) × 0.7 = PIT × 0.2 × 0.7	6 × 0.7 = 4 mg/day
PTIT due to refluxed and red cell-fixed radioiron: (RCIT – RCIR)	24 – 20 = 4 mg/day
SIT due to refluxed and red cell-fixed radioiron (SITr): (RCIT – RCIR) × 0.7	4 × 0.7 = 3 mg/day

0.7* is the approximation ratio of storage iron to total parenchymal tissue iron in the normal male.¹⁾

SIT/PIT/100 = 7/30/100 = 23%, RCIR/PIT = 2/3, and PTIT/PIT = 1/3.

SIT = SITf + SITr. PIT = RCIR + PTIT.