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males and females (76). Individuals with haemoglobin levels below the normal range are, by definition, anaemic (77). The WHO Global Database on Anaemia (55) defines haemoglobin thresholds for anaemia as 12.0 g/dl for non-pregnant women (≥15.00 years) and 13.0 g/dl for men (≥15.00 years). There are many causes of anaemia and anaemia due to iron deficiency is the most prevalent. The aim of haemoglobin screening is to ensure that the prospective donor is not anaemic. The lower limit of acceptable haemoglobin for blood donation should be set at a level that prevents the selection of anaemic individuals as blood donors and also minimizes the exclusion of healthy donors. Haemoglobin screening safeguards anaemic individuals from donating blood and also protects returning donors from donation-induced iron deficiency (DIID), the depletion of iron stores by repeated donations (78,79). Collecting a unit of blood from a donor with a normal haemoglobin level also provides good quality blood components, with adequate and consistent haemoglobin content in the collected blood. Haemoglobin and/or haematocrit are easily estimated by validated, simple, rapid and inexpensive methods, but are insensitive in assessing iron deficiency as 44 values start to fall only when iron stores are depleted. Nevertheless, they remain the most convenient measurement parameters at blood donation session and when recorded at each subsequent attendance, can detect anaemia and DIID. Donor haemoglobin and/or haematocrit levels should be measured immediately before each donation using a validated technique that is subject to quality control. Donors who do not meet the minimum haemoglobin levels for blood donation should be referred for further haematological investigation and treatment. They should be encouraged to return to donate when the anaemia has been successfully treated. Recommendations n In determining the lower limits of haemoglobin for whole blood donation and implementing haemoglobin screening, the BTS should consider: — Normal haemoglobin range among healthy individuals in the local population — A haemoglobin level of not less than 12.0 g/dl for females and not less than 13.0 g/dl for males as the threshold — Selection of a validated haemoglobin screening technique that is subject to quality control, the feasibility of its implementation, the availability of equipment and the training and skills of staff n Only sterile disposable lancets should be used for blood sampling n Donors whose haemoglobin levels are below the nationally-defined threshold should be deferred, counselled and referred for medical assessment 4.6.2 Frequency of donation and iron supplementation Iron deficiency is common worldwide and donation-induced iron deficiency is of particular concern in relation to women of childbearing age and adolescents. Adolescents of both sexes are also at risk of iron deficiency during the pubertal growth spurt, when the average daily total requirement of dietary elemental iron to be absorbed is 1.50 mg/day for males and 1.62 mg/day for female (54,55). A donation of 450 ml of blood removes 200–250 mg of haem iron. The average amount of stored iron (ferritin and haemosiderin) in a woman of reproductive age in the developed world is about 300 mg; hence, the donation of a unit of blood requires the subsequent mobilization of much or all of this reserve (80). In developing countries, many women have depleted iron stores and will inevitably be precipitated into negative iron balance by blood donation (54,55,76). Across the world, the minimum interval between whole blood donations varies between 56 days (8 weeks) and 16 weeks and different donation intervals are usually followed for male and female donors; in practice, some female donors are unable to give blood more than once or twice per year due to iron deficient states. There is a high prevalence of iron depletion in frequent blood donors; increasing the inter-donation interval would reduce the prevalence of iron depletion and deferral due to low haemoglobin (76,81,82). The standard approach for preventing donation-induced iron deficiency is universal screening and deferring those whose pre-donation haemoglobin is below a certain threshold. It is important to detect and manage the donation-induced iron depletion that inevitably accompanies regular blood donation (78). Reducing the frequency of blood donation is likely to reduce the prevalence of iron deficiency among blood donors, as might implementing routine iron supplementation (83). 45 The onset of DIID may be determined using full blood cell counts and red cell indices, including red blood cell distribution width (RDW), when measured serially in healthy donors from populations with a low prevalence of inherited conditions such

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