LITMIR.BIZ

4 Blood Donor Medical Assessment, Collection, and Complications

       Gary Bachowski MD, PhD

      The blood supply system in the United States has developed along two main tracks (see Chapter 2). One involves nonprofit community, regional, and national blood centers that obtain cellular elements and plasma from whole blood or apheresis donations provided almost exclusively by unpaid volunteers. Most of these products are used directly for transfusion.

      The other blood collection system involves large‐scale collection of plasma by plasmapheresis. This system consists of for‐profit organizations and almost all of this plasma comes from paid donors. This plasma is manufactured into plasma derivatives, such as albumin, coagulation factor concentrates, or intravenous immunoglobulin, and these are sold on the national and international market.

4.1 Blood collection

      Whole blood is collected by venipuncture from healthy adults into plastic bags containing a liquid anticoagulant preservative solution. The whole blood is separated into red blood cells, plasma, and occasionally platelet concentrate (see Chapter 5). The plasma can be: (a) frozen and used for transfusion, (b) further processed into cryoprecipitate (to be used for transfusion) and cryoprecipitate‐poor plasma (which can serve as a raw material for further manufacture of plasma derivatives), or (c) provided as a direct source of raw material for subsequent manufacture of plasma derivatives. Modifications can be made to these components to obtain blood products that will be effective for specific purposes. A complete list of components that can be produced from whole blood and are licensed by the US Food and Drug Administration (FDA) is provided in Chapter 5. Although blood banks may distribute some plasma derivatives, most are distributed through manufacturers by hospital pharmacies. Blood centers also produce platelets, red cells, plasma, and granulocytes by apheresis (see Chapter 6) in which the component(s) of interest is (are) removed in a blood cell separator and the remaining blood is returned to the donor.

Because blood is considered to be a drug and is regulated under FDA law, most aspects of potential donor selection and the collection of blood are carried out under requirements established by the FDA. This chapter attempts to provide concepts and rationale for blood donor assessment and blood collection but does not refer to every specific FDA requirement. However, it should be understood that all of these activities must conform to FDA requirements, which can be found in the Code of Federal Regulations and various FDA guidelines. For blood banks that desire accreditation by the AABB (American Association of Blood Banks), the standards of that organization must also be followed. The Technical Manual of the AABB [1] is an excellent reference that provides details for much of the content of this chapter.

4.2 Medical assessment of whole blood donors

The selection process for blood donors is designed to ensure the safety of the donor and to obtain a high‐quality blood component that is as safe as possible for the recipient (Table 4.1). In general, 10–15% of presenting donors are either deferred or provide an unsatisfactory unit of blood due to short‐term deferrals (e.g., hemoglobin), long‐term deferral (e.g., malaria), permanent deferral (e.g., hepatitis B/C), disease marker reactive donations, or an unsatisfactory collection process [2–4]. The loss of these potential donors and donations has a huge impact on the blood supply [5].

      A major factor influencing whether blood donors will make subsequent donations is their experience at each donation. Thus, it is important that the blood collection staff provide a warm, friendly, professional, and efficient environment in which the medical assessment and blood donation can take place.

      Registration

When the donor initially presents at the donation site, identifying information is obtained for the permanent record. This includes name, address, telephone number, birth date, social security number (if allowed in that state), and previous donation history, including any names under which previous donations might have been made. To prevent iron depletion, individuals may donate a red cell unit no more often than every 56 days, or 112 days if they are giving a double unit by automated collection. At the time of registration, the prospective donor is given information about blood donation, transmissible disease testing, and factors or behaviors that would preclude blood donation. Information may also describe the agencies that are notified in the event of a positive test result for a transmissible disease. In obtaining the medical history, a staff member asks or reviews donor responses to questions about these factors. Either at the time of registration or before the blood unit is made available for distribution, the identity of each donor must be checked against a registry of individuals known to be unacceptable as blood donors [6]. Although this process is required by the FDA and is widely used throughout the United States, there has never been a thorough study to establish its value, and some registries do not share information that could limit effectiveness.

Table 4.1 Strategies for collecting safe blood.

      There is no standard maximum age for blood donation. Most blood centers do not have a specific upper age limit and instead evaluate each donor individually. Elderly donors have more medical conditions and medications than younger donors, but they do not experience more adverse reactions to donation [7, 8]. Elderly donors have slightly decreased iron

Скачать книгу