Module 3 Blood Group Serology - World Health Organization

INTRODUCTIONTOMODULE3as a comprehensive resource that you can integrate into your owntraining programmes.Module 3 may contain some material which is new to you. Take as muchtime as you need to read through each section and mark anything thatyou find difficult. Then go back to those parts and reread them until youfeel sure that you are able to understand them. If you still find themcomplicated or are unable to complete some of the activities, seek helpfrom your trainer, your supporter or another senior colleague. Don’t beafraid to ask for assistance since what you are learning is extremelyimportant and will directly benefit the centre in which you work.Some sections may contain material which is already familiar to you. Ifso, read them through carefully as a means of revision and answer theself-assessment questions to make sure that your knowledge andpractice are completely up to date. Complete the activities – they willprovide you with a further check on your understanding and will help youto identify any improvements that you can make in your practice.1.2BEFORE YOU BEGIN THIS MODULEYou should already have completed the Introductory Module and mayalso have worked through other modules in this distance learningprogramme. During this period, you should have been in regular contactwith your trainer. You should already have had an opportunity to discussthe work you will be undertaking on Module 3 but, if this has not yet beenpossible, contact your trainer before you begin this module.When you started working through the Introductory Module, you wereasked to identify someone, ideally your supervisor, who would act as yourpersonal “supporter”. You should have been able to find someone whowas willing to meet with you regularly to discuss your progress andprovide assistance and support, particularly when you were developingand implementing your Action Plan. You now need to choose a supporterfor your work on this module – perhaps the same person or another seniorcolleague who has experience in blood grouping and compatibilitytesting.ACTIVITY 1Think about the people with whom you work, particularly yoursupervisor and other senior colleagues, who could support you whileyou are working through Module 3. Identify one person whom youthink would be willing to spend some time talking to you periodicallyabout your work on this module and helping you with any problemsthat you might face. Remember that it is important to choosesomeone who is prepared to discuss your ideas about ways ofimproving the service and to assist you in planning and implementingany changes that you identify as being needed as a result of yourwork on this module.Check that the person you have identified is prepared to help you. Ifyou have chosen a different supporter from the person you selected3

SECTION1for your work on other modules, explain how the learning programmeoperates and what the role of the supporter involves. Show thismodule to your supporter so that they become familiar with itscontent and approach. When you are preparing your Study Plan,arrange regular meetings to discuss your progress.If you have any difficulty in finding a suitable supporter in yourworkplace, talk to your trainer who will help to find someone tosupport you.Even though your supporter will be your main source of assistance, youwill also find it helpful to discuss your work on this module with yourcolleagues, particularly those who are also involved in blood groupingand compatibility testing.1.3MODULE 3: BLOOD GROUP SEROLOGYBlood transfusions are usually life-saving, but there are occasions whenthey cause degrees of morbidity and even mortality. Regrettably, someof these deaths are caused by poor laboratory practice, such as errorsin blood grouping or compatibility testing, perhaps because the personperforming the tests does not understand the scientific principles or isunable to interpret the results accurately. On other occasions, it isbecause blood or plasma has been selected or issued incorrectly.This module is therefore designed to help you to strengthen yourknowledge and skills in blood group serology to ensure that blood isalways safely and correctly issued for transfusion by your blood bank.Section 1: Introduction to Module 3 outlines the contents of the moduleand contains activities to help you to prepare for your work on it.Section 2: The Components and Functions of Whole Blood describes theconstituents of blood and explains their importance.Section 3: Basic Blood Group Immunology focuses on antigens,antibodies, the antibody immune response and antigen–antibodyreactions.Section 4: The ABO Blood Group System considers the importance of theABO blood group system in blood transfusion practice. It explains basicgenetics and the inheritance of blood groups, the development of A andB red cell antigens, the subgroups of the A antigen and high-titreantibodies.Section 5: The Rh Blood Group System considers the importance of theRh (Rhesus) blood group system in blood transfusion practice. It explainsthe genetics of the Rh system, the importance of correct RhD typing andtesting for the Du antigen.Section 6: Compatibility Testing and Issuing Blood focuses on compatibilitytesting and the procedures for selecting and issuing blood, both routinelyand in emergencies. It also covers procedures for investigating transfusionreactions, record-keeping and managing stocks of blood and plasma.4

INTRODUCTIONTOMODULE3Section 7: Techniques for Blood Grouping and Compatibility Testingfocuses specifically on the main techniques used in blood grouping andcompatibility testing. Instructions for performing these techniques areprovided in Appendix 1.Section 8: Action Plan is the final section in which you are asked to reviewall the ideas you have included in your Action List and to prepare an ActionPlan as a basis for improving working practices in your laboratory. You willfind the Action List for Module 3 on page 96.1.4MODULE OBJECTIVESThere are six overall objectives for this module which specify what youshould be able to do as a result of reading the text, answering the selfassessment questions, completing the activities and preparing yourindividual Action Plan.When you have finished working through this module, you should be ableto achieve the following objectives:Section 2Explain the functions of the main components of blood andtheir significance in blood transfusion practice.Section 3Explain the red cell antigen–antibody reaction and the factorsthat affect it.Section 4Explain the ABO blood group system and use the results of celland reverse ABO grouping tests to identify the blood groups ofdonors and patients.Section 5Explain the Rh blood group system, and identify when to useRhD positive or RhD negative blood and when to test for theweak D (Du) antigen.Section 6Explain the importance of compatibility testing and developand maintain appropriate procedures and records for the saferequest, selection and issue of blood under routine andemergency conditions.Section 7Explain the principles of the main techniques used in bloodgrouping and compatibility testing and perform them safely andaccurately.ACTIVITY 2Before you begin work on Section 2, you will find it helpful to assessyour current level of knowledge, skill and experience in relation to themodule objectives and to decide what you want to achieve by workingthrough the module. Look carefully at the module objectives and, foreach one, decide whether you have:5

SECTION1Rating(1–4)Module objectivesCommentsSection 2Explain the functions of the main components ofblood and their significance in blood transfusionpractice.Section 3Explain the red cell antigen–antibody reaction andthe factors that affect it.Section 4Explain the ABO blood group system and use theresults of cell and reverse ABO grouping tests toidentify the blood groups of donors and patients.Section 5Explain the Rh blood group system, and identifywhen to use RhD positive or RhD negative bloodand when to test for the weak D (Du) antigen .Section 6Explain the importance of compatibility testing anddevelop and maintain appropriate procedures andrecords for the safe request, selection and issue ofblood under routine and emergency conditions.Section 7Explain the principles of the main techniques usedin blood grouping and compatibility testing andperform them safely and accurately.1A high level of knowledge, skill and experience.2A reasonably good level of knowledge, skill and experience.3Some knowledge, skill and experience.4Little or no knowledge, skill or experience.The objectives are repeated in the table above. Note down your rating(1, 2, 3 or 4) for each objective and add any comments you wish tomake. Note any objectives that relate to areas of work that you donot currently undertake.You have now identified the areas that will be mostly revision for you andthe areas to which you need to pay particular attention. The moduleobjectives are designed to help you to assess your own progress. Whenyou reach the end of the module, you will be asked to look back at themto check whether you feel that you have achieved them. The mostimportant question to ask yourself then is whether you feel that you cando your job better as a result of your work on this module. If you feel thatyou would like to improve your knowledge, understanding and skills6

INTRODUCTIONTOMODULE3further, think carefully about the topics you would like to learn moreabout. Then talk to your supporter, supervisor or trainer about how youcan achieve this.1.5PLANNING YOUR STUDYSince you should already have completed the Introductory Module and,perhaps, other modules, you should be able to make a reasonableestimate of the amount of time that you will need to spend on Module3. Some of the activities may be time-consuming, but remember that youwill be able to complete most of them during the course of your normalwork.ACTIVITY 3Look quickly at the other sections in this module to get an idea of thecontent, level and approach and to assess how much of the materialis likely to be new to you. Also look at some of the activities toassess the kind of work that will be involved.Try to estimate how much time you will need to study each section,including answering the self-assessment questions and completingthe activities. Remember that you will also need to allocate time tomeet with your supporter and trainer and to prepare your Action Plan.Then talk to your supervisor about the amount of time you could beallocated each week, or each month, for your work on Module 3.Now fill in the Study Plan on page 8. Copy the ratings of yourknowledge, skills and experience from Activity 2 as they are anindication of how much time you will need to spend on each section.Then add the dates by which you plan to complete each section,taking into account your current knowledge, skills and experience inrelation to each module objective and the time you are likely to haveavailable for study. When you have arranged dates for meetings orother contact with your trainer and supporter, add these to your StudyPlan.SUMMARY1Module 3 focuses on blood grouping and compatibilitytesting and the correct issue of blood for transfusion.2You should identify a personal supporter to provideongoing support while you work through this module.3Before starting work on Module 3, you should review yourknowledge, skills and experience in relation to the moduleobjectives.4A realistic Study Plan will help you to organize your workon this module.7

SECTION1STUDY PLANSectionSection 2The Components andFunctions of Whole BloodSection 3Basic Blood GroupImmunologySection 4The ABO Blood GroupSystemSection 5The Rh Blood GroupSystemSection 6Compatibility Testing andIssuing BloodSection 7Techniques for BloodGrouping andCompatibility TestingSection 8Action PlanNotes8Rating(1–4)Planned completiondateMeeting dateswith trainerwith supporter

INTRODUCTIONTOMODULE3PROGRESS CHECKBefore moving on to Section 2, spend a few minutes thinkingabout whether you have achieved the learning objectives forSection 1. These were to:1Explain the purpose of Module 3.2Identify a personal “supporter” who can assist youthroughout your work on this module.3Assess your current knowledge, skills and experience inrelation to the objectives of this module.4Make a realistic Study Plan for your work on this module.If you feel confident that you have understood everything, turnto Section 2. If you feel that you need more information aboutModule 3 or the learning programme as a whole, contact yourtrainer to discuss anything you are unsure about or talk to yoursupporter.9

SECTION22The Components andFunctions of Whole BloodThe purpose of this section is to help you to understand the constituentparts of blood and their functions.LEARNING OBJECTIVESWhen you have completed this section, you should be able to:101Describe the main components of blood.2Explain the function of these components of blood andtheir importance in transfusion practice.

plasmaplasma:: The fluid part ofblood which carries thecells and other substancessuch as proteins, clottingfactors and chemicals.erythrocyteerythrocyte:: The redblood cell (the mostnumerous blood cell),which contains the redpigment haemoglobinand is responsible fortransporting oxygen tothe body tissues.leukocyteleukocyte:: A family ofnucleated white cellsinvolved in fightinginfection and makingantibodies.thrombocytethrombocyte:: A bloodplatelet, which plays amajor role in the bloodclotting mechanism.coagulationcoagulation:: Clotting ofblood which takes placewhen blood is collectedinto a dry container orreaches an open wound.reticuloendothelialsystem:: A collection ofsystemendothelial cells thatproduce macrophages orlarge mononuclear cells.They are found in the bonemarrow, liver, spleen andlymph glands.haemoglobinhaemoglobin:: A red fluidfound in the red blood cellswhich is made up of iron(haem) and polypeptidechains (globin).THECOMPONENTS2.1WHOLE BLOODANDFUNCTIONSOFWHOLEBLOODBlood is a complex fluid consisting of different blood cells suspended ina yellowish liquid called plasmaplasma. The blood cells comprise a mixture oferythrocytesleukocytesred cells (erythrocyteserythrocytes), white cells (leukocytesleukocytes) and plateletsthrombocytes(thrombocytesthrombocytes). The plasma contains many different proteins, chemicalcoagulationsubstances, clotting (coagulationcoagulation) factors and numerous metabolicsubstances.Blood serves as a transport medium for carrying all its differentcomponents to the different organs of the body.2.2RED BLOOD CELLS (ERYTHROCYTES)Red cells appear under the microscope as biconcave discs (see Figure1). They are extremely small, with a diameter of 7.2 microns. There areapproximately 5 million of these cells in each cubic millimetre (mm3) ofblood (5 x 1012/L). They are made in the bone marrow and, when theyare mature, enter the bloodstream where they have a lifespan ofapproximately 120 days. After this, they break down and are removed bycells of the reticuloendothelial systemsystem. These cells are highly specializedand are scattered throughout the body. They are found mainly in the bonemarrow, liver, spleen and lymph glands.Red cells are filled with a substance called haemoglobin and theirprimary function is to carry oxygen to the body tissues.2.3HAEMOGLOBINHaemoglobin is a large complex molecule made up of iron-containingmolecules called haem which are attached to polypeptide chains calledglobin. Haemoglobin is a red fluid found in the red blood cells. It has theability to combine reversibly with oxygen and carbon dioxide. Its mainfunction is to transport oxygen to the various tissues to provide the bodywith its energy and heat. Oxygen is taken up in the lungs and pumped bythe heart to the tissues. After it has been used, the oxygen is replacedby unwanted carbon dioxide which is carried back to the lungs by the redcells and a small amount by plasma. Here it is given up and replaced withfresh oxygen ready to start the next circulatory cycle.Haemoglobin levels are measured in grams of haemoglobin per decilitreof blood. Men have a slightly higher average haemoglobin level thanwomen: men average between 13.5 and 17.0 g/dl and women between12.0 and 16 g/dl.Figure 1: Side and top view ofa normal red cell, showing itsbiconcave formSide viewTop view11

SECTION2The minimum haemoglobin levels accepted by blood transfusion centresin many countries are as follows: males: 13.5 g/dl females: 12.5 g/dl.Haemoglobin levels can be measured in different ways, but the bestmethod is either a colorometric or a photometric technique.The level can also be estimated, as opposed to being measured, bycomparing its specific gravity with the specific gravity of a preparedcopper sulfate solution of known strength. This technique is widely usedin blood transfusion practice as it is suitable for use in places whereelectricity supplies are poor or are not available. Acceptable donorhaemoglobin levels are determined by confirming that a drop of blood cansink in a copper sulfate solution of a specific gravity of 1.055 for men andof 1.053 for women. Appendix 1 in the Introductory Module contains anexample of a standard operating procedure for the preparation of coppersulfate solution and Appendix 5 in Module 1 contains examples ofstandard operating procedures for haemoglobin screening using thecopper sulfate method.granulocytegranulocyte:: A whiteblood cell (leukocyte)containing neutrophil,eosinophil or basophilgranules in thecytoplasm.lymphocytelymphocyte:: A type ofwhite blood cell formed inthe lymph nodes. Thereare two kinds oflymphocyte: Blymphocytes whichproduce circulatingantibodies and Tlymphocytes which areresponsible for thecellular immuneresponse.monocytemonocyte:: A largeleukocyte which ingestsbacteria and other foreignbodies.neutrophilneutrophil:: A member ofthe family of white cellsinvolved in fightinginfection.eosinophileosinophil:: A member ofthe family of white cellsinvolved in fightinginfection.basophilbasophil:: A member ofthe family of white cellsinvolved in fightinginfection.12The WHO Haemoglobion Colour Scale is another simple method ofestimating haemoglobin levels (see Module 1, Appendix 6). It is aninexpensive clinical device that provides a reliable method for screeningfor the presence and severity of anaemia.ACTIVITY 4What are the minimum haemoglobin levels that are accepted amongblood donors in your donor clinic? Briefly describe the methods thatare used to measure them.2.4WHITE BLOOD CELLS (LEUKOCYTES)Leukocytes are a family of nucleated cells consisting of granulocytesgranulocytes,monocytes. There are three different forms oflymphocytes and monocytesgranulocyte: neutrophilsneutrophils, eosinophils and basophilsbasophils.Under normal conditions, granulocytes are derived solely from the bonemarrow. Small numbers of lymphocytes are produced in the bonemarrow, but the main supply comes from the lymphatic tissue andthymus. The site of production of the monocyte is still uncertain; it isprobably produced at any reticuloendothelial tissue site, particularly thespleen.The normal number of circulating leukocytes in the blood is far less thanthe number of red cells. In a normal hea

4 THE ABO BLOOD GROUP SYSTEM 25 4.1 The ABO Blood Groups 26 4.2 Basic Genetics of the ABO Blood Groups 27 4.3 Demonstrating ABO Blood Groups 29 4.4 Development of the A and B Red Cell Antigens and Antibodies 30 4.5 The Subgroups of the Antigen A 30 4.6 Anti-A 1 and Anti-AB in Blood Grouping Tests 31 4.7 IgM and IgG (Naturally-occurring and Immune)