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Blood is drawn from a vein in the antecubital fossa. The vein selected should be large enough to accommodate approximately a 16‐gauge needle. Careful selection of the vein makes the venipuncture quick and easy, thus providing good blood flow and a quality component but also minimizing the discomfort to the donor and making the donation experience as pleasant as possible. The choice of the vein will also minimize the likelihood of inadvertently damaging a nerve or puncturing an artery (see the later Adverse Reactions section). A blood pressure cuff is usually used to impede venous return and distend the vein.

To minimize the chance of bacterial contamination, the blood must be drawn from an area free of skin lesions, and the phlebotomy site must be properly cleansed (Table 4.3). It is not possible to sterilize the skin, but steps are taken to greatly reduce the level of skin flora. A one‐step skin preparation using a chlorohexidine solution in 70% isopropanol is now recommended. Alternatively, a two‐step prep—scrubbing with a soap solution, followed by tincture of iodine or iodophor complex solution—may be used [1, 49, 50]. Preference for the prep method is often dependent on any history of donor allergies or previous reactions to the scrub. The selection of the venipuncture site and its sterilization are very important steps, because bacterial contamination of blood can be a serious, even fatal complication of transfusion (see Chapter 16).

Table 4.3 General procedure: donor arm preparation for blood collection.

Source: World Health Organization. WHO Guidelines on Drawing Blood: Best Practices in Phlebotomy. Geneva: World Health Organization, 2010. © 2010 World Health Organization.

Apply tourniquet or blood pressure cuff. Identify venipuncture site; then release tourniquet or cuff.Use a product combining 2% chlorhexidine gluconate in 70% isopropyl alcohol. Cover the whole area and ensure that the skin area is in contact with the disinfectant for at least 30 seconds.Allow the area to dry completely, or for a minimum of 30 seconds by the clock or as directed by the manufacturer.Whichever procedure is used, DO NOT touch the venipuncture site once the skin has been disinfected.