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as thalassaemia trait. The more sophisticated red cell parameters on modern cell counters are even better indicators of DIID onset, even possibly in the co-presence of thalassaemia trait, but are more expensive and usually not available at blood donation sites. Haemoglobin estimation alone in regular blood donors may not be adequate and serum ferritin estimations may need to be done to detect pre-clinical iron deficiency state. Regular ferritin measurement is a useful indicator for iron depletion in blood donors. (84,85,86,87,88). If the BTS has access to facilities for monitoring donor iron stores by measuring serum ferritin concentrations, individual donor algorithms for donation frequency and iron supplementation may be developed (78,80,81,83,85,89,90,91,92,93). In some circumstances, the more expensive but informative determination of serum soluble transferrin receptor concentrations (STR) gives an even better indication of DIID. Iron supplementation of blood donors has been proposed for routine implementation and several pilot operational and clinical trials have been conducted (83). Donor iron stores may be replenished by giving oral iron supplements and this particularly needs to be considered for repeat and regular blood donors. Indiscriminate long-term supplementation with iron salts at a high dose is, however, not recommended, because of: n Possible masking of other pathological causes of iron deficiency, such as gastro-intestinal bleeding n Risk of giving iron salts to people with undiagnosed hereditary haemochromatosis or other inherited iron-overloading tendencies (78) n Toxicity if accidentally ingested by children. Some of these concerns may be avoided by using low-dose iron preparations or carbonyl iron. Such preparations are better tolerated, less toxic and can be safely used to reduce donation intervals. Donors giving platelets or plasma by apheresis may donate more frequently than whole blood donors. A minimum inter-donation interval of 4 weeks for platelet donors and 2 weeks for plasma donors is generally recommended, provided that haematological and biochemical parameters are monitored and remain within acceptable limits (94). The interval before an apheresis platelet or plasma donation should be at least 4 weeks following a whole blood donation, an apheresis red cell donation or a failed return of red cells during apheresis (70). The inter-donation interval between double red cell donations should be 6 months. If a double red cell donation is given following whole blood donation, the interval should be 12 weeks for males and 16 weeks for females. Recommendations n The minimum interval between donations of whole blood should be 12 weeks for males and 16 weeks for females n The minimum interval between donations of platelets should be 4 weeks n The minimum interval between donations of plasma should be 2 weeks 46 n The minimum interval before an apheresis platelet or plasma donation should be 4 weeks following a whole blood donation, an apheresis red cell donation or a failed return of red cells during apheresis n In determining the frequency of donation and whether iron supplementation is given, the BTS should consider: — The need for longer donation intervals for young donors and female donors of childbearing age — Assessing the feasibility and affordability of providing iron supplementation to donors susceptible to donation-induced iron deficiency, especially women, adolescents, and repeat and regular donors — Exploring access to facilities for monitoring serum ferritin concentration and the feasibility of developing and implementing individual donation intervals 4.7 FLUID INTAKE AND FOOD Most BTS guidelines recommend that donors should maintain their usual food and fluid intake before donation but should avoid heavy or fatty meals which may result in a lipaemic donation that may need to be discarded. The risk of adverse events in fasting donors has not been investigated, but there is evidence that an intake of 500 ml of drinking water immediately before donation may reduce the risk of a vasovagal reaction (95,96,97). Where possible, donors should have access to drinking water in the blood centre before donating. Fasting donors should have had some fluid intake in the four hours prior to donation. In countries where prolonged fasting is practised, blood collection sessions may be scheduled after they have taken food and fluid. Recommendation n The BTS should consider providing 500 ml drinking water to donors before donation to minimize the risk of vasovagal reactions 4.8 GENDER 4.8.1 Pregnancy, lactation and menstruation The average woman needs about 350–500 mg additional iron to maintain

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