Guidelines for compatibility procedures in blood transfusion laboratories.

SECTION 1 INTRODUCTION 1.1 Purpose of the guidelines The effective development and maintenance of satisfactory standards in pretransfusion testing requires a structured approach in the adoption of a quality system. Technical errors, clerical errors, the use of nonvalidated techniques or equipment and noncompliance with established procedures may result in missed incompatibilities and immediate or delayed haemolytic transfusion reactions (Love et al., 2002). The purpose of these guidelines, which replace those previously published in 1996 (BCSH, 1996b), is to define the laboratory processes and procedures that should be adopted to undertake pretransfusion testing. These guidelines are formulated from expert opinion and based on the recommendations of Clinical Pathology Accreditation (CPA, UK), Guidelines for Blood Transfusion Services in the UK and data from UKNEQAS (BTLP) (Knowles et al., 2002) and the Serious Hazards of Transfusion (SHOT) haemovigilance scheme. Where evidence exists to support new and potentially contentious recommendations, this is referenced in the text. 1.2 Elements in pretransfusion testing 1.2.1 ABO and D grouping of the recipient. 1.2.2 Antibody screen of the recipient, or mother in the case of neonatal transfusion, which, in the event of a positive screen, should be followed by antibody identification. 1.2.3 A computer or manual comparison of current results with any historical record. These three elements constitute a group and screen. 1.2.4 Donor red cell selection and crossmatching, which may involve serological testing between patient serum/plasma and donor red cells or electronic selection and issue. 1.2.5 There should be a documented procedure for dealing with emergencies. In clinical emergencies , the recipient's need for immediate red cell support may dictate that pretransfusion testing is abbreviated or even that group O blood be issued. 1.3 Clinical significance of red cell antibodies 1.3.1 Clinically significant antibodies are those that are capable of causing patient morbidity due to accelerated destruction of a significant proportion of transfused red cells. 1.3.2 Anti-A, anti-B and anti-A,B must always be regarded to be of clinical significance. 1.3.3 With few exceptions, red cell antibodies that are potentially clinically significant are only those which are reactive in the indirect antiglobulin test (IAT), performed strictly at 37 C. 1.3.4 In certain clinical circumstances, e.g. massive blood loss, the recipient's need for red cell transfusion may necessitate the use of incompatible units. 1.3.5 Recommendations for the selection of red cells for transfusion to patients with alloantibodies are given in Table 1. 1.3.6 The use of antibody cards, produced …