Table 6. HAIR values for typical clinical settings.

		US values based on RDA, mg/day		UK values based on RNI, mg/day
Setting	Approximate volume loss (ml)	Males or post menopausal females	Pre menopausal non pregnant females	Males or post menopausal females	Pre menopausal females
No additional losses	0	8	18	8.7	14.8
Blood donation every 3 months	470	27.6	37.5	20.6	26.7
Hemorrhagic hemoglobin fall* of
1 g/dl, e.g normal peri-partum loss [52]	470	27.6	37.6	20.6	26.7
2 g/dl e.g. TURP; colectomy, minor postpartumhemorrhage [52]	940	47.2	57.2	32.6	38.7
3 g/dl e.g. moderate post partum hemorrhage [52]	1410	66.8	76.8	44.5	50.6
4 g/dl e.g. nephrectomy [51]	1880	86.3	96.3	56.5	62.6
Femoral head fracture [53]	611	33.5	43.5	24.2	30.3

HAIR values were calculated by the formula given in the Methods, correcting over 3 months. *HAIR values can be extended to incorporate existing deficits manifest by hemoglobin falls, although other guidance exists in this setting; [22] these figures exclude any hemorrhagic losses and hemoglobin falls that are corrected by transfusions, since the transfused red cell iron content remains available for body stores. TURP, transurethral resection of the prostate. The reasons for the differences between columns are that the recommended dietary iron intake for premenopausal females is substantially higher than for post-menopausal females and for men, and because normal dietary intake recommendations vary between countries: In the UK, the respective iron Reference Nutrient Intake (RNI) values are 14.8 mg/day and 8.7 mg/day [64]. In the US, premenopausal women are advised to consume 18 mg/day, increasing to 27 mg/day when pregnant, compared to 8 mg/day for men and post-menopausal women (recommended dietary allowance, RDA, as used in calculations presented in the current study). [2] UK HAIR values are therefore lower than US-based HAIR values because of the lower recommendations for premenopausal women, and because the UK increment of 6.1 mg/day applies instead of the US increment of 10 mg/day for premenopausal women. The principles and calculation can be extended to any other set of dietary allowances.