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iron balance during pregnancy (54,55). Female donors should be deferred during pregnancy and for a sufficient time after delivery (or following abortion or miscarriage) and during lactation to allow for the recovery of iron stores. Menstruation is not a reason for deferral. However, women who report regular excessive menstrual bleeding and are found to have low haemoglobin levels should not donate blood and should be referred for medical assessment (90). Contracting and relaxing the muscles in the legs, arms and abdomen during donation may reduce the risk of vasovagal reactions, particularly among female donors (98,99,100,101). 47 Recommendations n The BTS should encourage donors to practise applied muscle tension during blood donation Accept n Female donors during menstruation, provided that they feel well and meet the minimum haemoglobin level for blood donation Defer n Female donors during pregnancy and up to 6 months after delivery or termination of pregnancy n Female donors during lactation 4.8.2 Reducing the risk of transfusion-associated acute lung injury (TRALI) The gender of the donor may influence the type of blood component prepared from the donation. Plasma-rich blood components from multiparous women are more likely to cause TRALI and related disorders than those from males, because plasma from such women is likely to contain alloimmune-reactive antibodies; these include antibodies to human leucocyte antigens (HLA) or to human neutrophil antigens (HNA), which are transferred passively during transfusion, to the possible detriment of a recipient who possesses the corresponding antigen (102,103,104). Recommendations n The BTS should consider: — Maximizing the collection and production of plasma and platelet concentrates from male donors — Screening multiparous female donors for HLA and/or HNA antibodies 4.9 OCCUPATION AND LEISURE ACTIVITIES Delayed vasovagal reactions, defined as occurring after the donor leaves the blood donation site but within 24 hours of donation, are uncommon (reported as 46:100 000) (105). However, if the donor is in a hazardous situation, a delayed vasovagal reaction may put the donor and others at risk of harm. For this reason, most BTS advise donors in hazardous occupations (e.g. emergency services, working at heights) not to resume work for at least 24 hours after blood donation. Air crew are subject to their own regulations which do not permit blood donation within specified time limits (106). Similarly, donors are generally advised not to undertake strenuous physical activities for up to 24 hours after blood donation. Some occupations (e.g. health-care workers, police, military personnel, workers with animals) carry an increased risk of exposure to blood-borne infections, although confirmed transmission is relatively rare (107,108,109,110,111). While such individuals should have been immunized against relevant diseases, where possible, donors in these occupations should be questioned about possible exposure risk (e.g. needlestick injuries, blood splashes, bites) and a deferral 48 period, usually of 6–12 months applied, based on the incubation period of the relevant infection. Sex workers are at particular risk of transfusion-transmissible infections and should not be accepted as blood donors (also refer to Section 7.9.1 on highrisk sexual behaviours). 4.10 SPECIAL CONSIDERATIONS FOR DONOR SELECTION FOR APHERESIS DONATIONS Apheresis is the process by which the required component of whole blood is separated and collected from the donor using an automated blood cell separation device. Components that can be donated by apheresis include platelets (plateletpheresis), plasma (plasmapheresis), leucocytes (leucapheresis) and red blood cells (erythrocytapheresis). Medical criteria for the acceptance of blood donors in respect of the donor’s health should be the same for donors of whole blood and of blood components obtained by apheresis. Additional donor selection criteria pertaining to apheresis donations are recommended in the relevant sections in this document. Detailed recommendations regarding the volume and frequency of apheresis donations are outside the scope of these guidelines. In addition to meeting the selection criteria required for whole blood donation, donors giving apheresis donations should also meet requirements that are specific for the type of apheresis procedure and the component collected (70,112,113,114). For apheresis platelet donation the donor’s platelet count should be above 150 x 10 9/L. For apheresis plasma donation, the donor’s total protein level should be greater than 60 g/L. For double red cell apheresis, donors of either gender require a minimum haemoglobin level of 14.0 g/dl (68). 49 5 Donor medical history I: Non-communicable diseases Having

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