Dear Sir,The Rh blood group system is determined by the highly homologous RHD and RHCE genes located on the first chromosome, which encode for the RhD and RhCE polypeptides. D antigen is of special clinical relevance in the fields of transfusion medicine and obstetrics. Owing to its high immunogenicity, D antigen can induce the production of alloantibodies and thus cause posttransfusion haemolytic reaction and haemolytic disease of the newborn (Wagner et al., 2000).About 0·2-1% of the European population are carriers of structurally altered RHD alleles encoding for various types of weak D proteins. At the molecular level, point mutations resulting in amino acid substitutions in the intracellular or transmembranous segments of RhD protein are causing weak D phenotypes. More than 170 different RHD alleles closely related to the expression of the respective D phenotype, including more than 70 weak D types, have been discovered to date (Flegel, 2007). Some weak D types (types 1, 2 and 3) are not associated with the development of alloantibodies; however, alloimmunisation in weak D types 4·2, 11 and 15 carriers have been reported (Flegel, 2006). Owing to the extremely small phenotypic variation, particular weak D types are very difficult to differentiate by serology and can only be identified by molecular methods, thus enabling definitive decision on the mode of transfusion treatment and the need of anti-D prophylaxis in pregnant women. The individuals who are carriers of weak D types 1, 2 and 3 can receive transfusion of D+ red blood cell (RBC) units, although such pregnant women do not require anti-D prophylaxis. Thus, the unnecessary utilisation of D− RBC units and RhIg is avoided (Flegel and Wagner, 2002).Particular segments of the RHD gene sequence are multiplied by RHD genotyping using primers specific for the known mutations characterising particular weak D types by use of the polymerase chain reaction with sequence-specific priming (PCR-SSP). This procedure is employed to determine polymorphism of the weak D types.

Quality indicators are one of the quality management system (QMS) tools to monitor and control efficiency of the system key segments, while the results collected serve as a basis for implementation of corrective measures and continuous quality improvement. There are several classifications of quality indicators. According to the objectives of their establishment and utilization, they can be internal and external. In line with the tripartite quality model, quality indicators can be classified as structural indicators, process indicators and outcome indicators. Quality indicators should ideally possess a number of attributes. Besides objectivity (measurability), the most common requirements are as follows: importance and potential for use, reliability and validity. Quality indicators offer the possibility of fast and simple insight into the level of product and service quality and their pattern over time to the interested parties within and outside the institution. Although quality management has long been recognized as being of utmost importance in transfusion medicine, quality indicators as a QMS tool did not receive due attention until recently. Implementation of quality indicators is a complex process which requires scientific approach as well as testing and verification before routine usage. Quality indicators are defined on the basis of scientific concepts, own experiences, results of literature searches, discussion with experts within and outside the institution, etc. On setting quality indicators, the numerator and denominator should first be strictly defined. Quality indicators should be monitored continuously, including trend monitoring and detection of deviations. Whenever considered necessary, appropriate corrective measures have to be undertaken.

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Transfusion medicine has a specific position relative to other fields of medical science. A series of laboratory and clinical medicine activities and pharmaceutical-like manufacture, with tight interaction of various professionals are involved in the complex chain of transfusion medicine, from the promotion of blood donation through the utilization of blood products. Maintaining constant high quality and safety of the products and services required by blood donors, patients and public at large are the prime and foremost goals to be pursued in transfusion medicine. These supreme goals can only be achieved through efficient quality management in all segments and with due support from all those involved in this complex system. Recognizing quality as a necessity, transfusion services all over the world have introduced or are just being introducing quality management systems according to particular standards and regulations. In EU countries, quality management in blood establishments is legal obligation defined by the 2005/62/EC Directive. Only a comprehensive and integrated quality management system can guarantee quality in a continuous way. Standard requirements and specifications of such an integrated system based on GMP and ISO 9000 series standards are elaborated in this paper.

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