Blood Transfusion and Agglutination Quiz

Blood Bank Procedures to Give Blood Safely

• Procedures are in place to ensure safe blood administration, avoiding predictable reactions and complications.
• Blood must be correctly administered to the correct patient for the intended purpose.

Contents

• Process Overview: Sample requirements, rationale for testing, and reasons for administering blood are covered.
• Blood Grouping and Antibody Screening: Techniques and processes for blood grouping and antibody screening are detailed.
• Antibody Identification: Tests, theory, and procedures are explained.
• Phenotyping and Selecting Blood: Methods for identifying blood types and selecting the appropriate blood.
• Crossmatching: Electronic and serological crossmatching processes are explored.

Learning Aims and Objectives

• Learning objectives for the presentation are not explicitly detailed within the provided content.

Process Overview: Sample Requirements, Rationale for Testing, and Reasons for Administering Blood

• Guidelines for blood samples, rationale for testing, and justification for blood administration are outlined.
• Blood administration must avoid predictable reactions.

Provision of Blood for Patients

• Blood administered must not cause reactions.
• Correcting the reason for administering the blood.
• Administering to the right patient, and avoiding complications.

Compatibility Schematic

• The compatibility schematic outlines a process for determining blood compatibility.
• Starts with blood group and antibody screening.
• Key steps include identifying the antibody, determining clinical significance, and performing serological crossmatch or electronic matching.

Sample Acceptance Criteria for Crossmatch

• Patient identification is crucial with five points.
• Samples are handwritten.
• Samples must be collected within 72 hours of the last transfusion.

Principles of Compatibility

• Compatibility is linked to the blood product type.
• Red Cells: Correct anaemia.
• Platelets: Correct thrombocytopenia.
• Fresh Frozen Plasma: Prevent microvasculature bleeding due to loss of clotting factors. Treats coagulation deficiencies.
• Red cells must match antigen and plasma groups.
• Prevents immediate and delayed haemolytic transfusion reactions.
• Plasma and platelets must be matched by antibody type for safety.
• Platelet antigens can cause reactions and reduce therapeutic benefit.

Blood Grouping and Antibody Screening

• Forward Grouping: Detects antigens on red blood cells, using known antisera to identify different A subtypes.
• Reverse Grouping: Detects antibodies in the plasma/serum of the patient, using known red blood cells to identify antibodies.
• RhD Typing: Important for detecting Partial D groups.

Antibody Screen

• This process confirms the presence or absence of antibodies.
• Reagent screening cells must express certain antigens, such as R2R2/R1R1 or R1wR1, K, k, Fya, Fyb and other specific antigens. These screening cells are used to check for antibodies in the recipient's blood.

Antibody-Antigen Reaction

• Reactions are based on physical interactions (hydrophobic/hydrophilic, electrostatic) that are complementary. Shape, charge, and water interactions.
• Antibody and antigen specificity is due to hypervariable regions.
• The interaction between these antibodies and antigens is held together by various weak non-covalent forces, including electrostatic forces, hydrogen bonds and van der Waals forces and hydrophobic bonding.

Affinity Versus Avidity

• Affinity: Describes the binding strength of a single antibody to a specific epitope.
• Avidity: Represents the sum of the binding strengths of multiple antibodies to multiple epitopes on the same antigen.
• Titre: Indicates the amount of antibody available to bind to an antigen.

Haemagglutination: Sensitisation and Agglutination

• These processes are central in determining blood compatibility through visually identifying agglutinins.

Factors Affecting Sensitisation

• Electro-repulsion: Electrostatic inference with binding.
• Steric Hinderance: Physical interference with epitope binding.
• Temperature: Incubation temperature is important for antibody detection.

Test Principles (Low and Normal Ionic Strength)

• Procedures for testing blood under different ionic strength conditions, such as low and normal ionic strength, are compared and described.
• Variables such as incubation times (15 mins or 45 mins) are identified.
• Centrifugation and washing steps are included.

ID Panel Profile

• This table identifies various blood antigens, including Rh (C, c, D, E, e), MN, Ss, and other blood groups, for example, K, k, Fy, and other antigens.
• Results are presented in a table format indicating the presence (+) or absence (-) of various antigens in a given sample.

Enzyme Treatment of Red Cells

• Glycolax is reduced
• Components of glycolax (sialic acid and sugar residues), are cleaved.
• Specific blood group antigens are cleaved as well, including certain M, N, S, s, Fya, and Fyb antigens.
• Negative charges are reduced.
• It enhances reactions related to ABO, Rh, Lewis, Kell, and Kidd blood groups.

Enzyme Degradation of Red Cell Antigens

• Enzymes break down specific compounds.
• Example of protein alterations within the red blood cell system.

Antibody Detection Methods (Column Agglutination Technology)

• Various technologies for antibody detection are described.
• Column agglutination technology (CAT) or gel card technology are presented.
• Procedure outlines steps for incubating serum/cell mixtures at a specific temperature and centrifugation steps. Methods like Diamed and BioVue Systems are included.

Antibody Detection Methods (Solid-Phase Technology)

• Capturing specific antibodies on solid surfaces.
• The methods are employed in microtiter wells and use antigens bound to surfaces for antibody detection.
• Solid-phase techniques use a microplate, with coated antigens. The test serum is applied, and antibody-antigen binding is identified by the presence of added indicator cells. Solid phase tests can be used to find IgG antibodies.

Reading & Grading Agglutination Reactions

• Qualitative interpretations of blood agglutination tests are described.
• Different grades of agglutination are listed.
• 5 is completely clumped, while 0 is the absence of agglutination.

DiaMed - Reaction Grading Chart

• Visual aids are used which help clarify the interpretation of the reaction grades.
• A visual description of the various stages of reactions.

Microscopic Examination of Agglutination

• Microscopic examination of reactions is mentioned.
• Images of results in different conditions (or different degrees of agglutination).

Phenotyping, Selecting Blood

• Procedures for determining blood types and selecting suitable blood units for patients are described.
• Compatibility between ABO and Rh D types is essential and is a minimum requirement, and K negative is needed in certain at-risk demographics.
• Consideration must be given to other medical conditions that may influence the selection process (e.g., sickle cell trait).

Selecting Blood

• Suitable blood types for special considerations are mentioned. This includes antigen-negative, CMV negative, irradiated and sickle negative transfusions.

DAT

• Types of DATs and their clinical significance are noted.
• Warm clinically significant antibodies (IgG positive and C3b/C3d positivity).

Phenotyping

• This includes determining whether an antigen is present or not in a patient sample.
• Methods and criteria for determining negative antigens for patients and tests necessary for determining if antibodies are present.

Crossmatching: Electronic and Serological

• Both electronic and serological methods for crossmatching are covered.
• Red cell compatibility (ABO and Rh D) to ensure safety.
• Plasma and platelet compatibility are also important.

Crossmatching

• Red cells, plasma, and platelets must be compatible in crossmatches.
• Key demographic differences are considered like females of childbearing age.

Electronic Crossmatching

• Steps for determining blood compatibility electronically.
• ABO and RhD typing must be performed for a patient electronically and serologically.
• System checks for antibody screen matches, donor phenotypes, and patient information encoded via barcodes.

EI (Electronic Issue)

• Key areas of compatibility are highlighted.
• ABO and Rh phenotype matching, including consideration for females is stated.
• Electronic linkage between patient and donor data is essential.
• Product assignment must be exclusive to a single recipient.

Blood Tracking System

• Tracking blood units through different stages is detailed.

Serological Crossmatching

• Phenotype units are selected.
• Donor red blood cells are reacted against recipient plasma/serum for compatibility assessment.
• The likelihood of reactions from existing antibodies may be predicted from antibody testing.
• A negative result is the ideal outcome.

Compatibility Versus Suitability

• Differentiates between blood compatibility and suitability.
• Blood is compatible if there's no indication of a reaction.
• Blood is suitable when a crossmatched test result is positive but there are no clinically significant antibodies interfering or issues with autoantibodies.

Reactions and Events

• Causes of errors could include wrong patient/product identification, errors in samples, bed side errors, incorrect product identification, and documentation issues.
• Reaction types from transfusion (e.g. adverse reactions) are described.