Blood Transfusion and Agglutination Quiz

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Questions and Answers

What result indicates that the indicator cells fell to the bottom of the well during the agglutination test?

Indicator cells adhere to the well sides forming a mat

Cloudy red supernatant with numerous small clumps

The cells agglutinate into several large clumps

No antibody is bound, seen as a button (correct)

Which of the following is NOT an advantage of solid-phase technology?

Requires minimal technical expertise (correct)

Less subjective reading of results

Automation capabilities for result processing

Increased sensitivity due to stable reactions

In the grading system for agglutination reactions, what does a grade of '4' indicate?

Red cells agglutinated in several large clumps, supernatant clear (correct)

Complete agglutination of all red cells in one clump

No agglutination and a very red cloudy mixture

Many medium sized agglutinates, clear supernatant

What is a significant disadvantage when using commercial kits for solid-phase technology?

High cost consumables Signup and view all the answers

For selecting blood for patients with special considerations, which of the following must be met?

Antigen negative and CMV negative Signup and view all the answers

Which of the following is NOT a requirement for blood administered through transfusion?

It should complicate patient care in the long-term. Signup and view all the answers

What is the purpose of antibody screening in blood transfusions?

To detect potential harmful antibodies that can cause reactions. Signup and view all the answers

Which of the following does NOT qualify as a part of the sample acceptance criteria for crossmatching?

The sample collection must occur within 24 hours before transfusion. Signup and view all the answers

Why is it necessary to phenotypically confirm antigen-negative blood?

To prevent auto-antibody formation in the patient. Signup and view all the answers

What information is required in the five points of patient ID for sample acceptance?

Patient's first name, surname, date of birth, hospital number, and date/time of sample. Signup and view all the answers

In the compatibility schematic, what does a 'clinically significant' antibody mean?

An antibody that could cause a serious reaction in a transfusion. Signup and view all the answers

What is the main rationale for conducting an electronic crossmatch?

To reduce the chances of clerical errors in blood matching. Signup and view all the answers

What is one major factor influencing the binding of antibodies to antigens?

Steric hinderance Signup and view all the answers

Which temperature is minimally required for antibodies to exhibit clinical significance in hemolysis?

32°C Signup and view all the answers

How does the ionic strength of a solution affect antibody sensitization?

It reduces electro-repulsion. Signup and view all the answers

What is the role of the RES (reticuloendothelial system) in extravascular hemolysis?

To eliminate C3b deposition. Signup and view all the answers

What effect does enzyme treatment (such as with papain or bromelain) have on red blood cells?

Cleaves off sialic acid and sugar residues. Signup and view all the answers

In the context of antibody identification, what does a positive antibody screen signify?

Presence of clinically significant antibodies. Signup and view all the answers

What is the required volume of plasma in a low ionic strength sensitization test protocol?

1-2 vol. Signup and view all the answers

What minimum incubation time is required for normal ionic strength sensitization at 37°C?

45 minutes Signup and view all the answers

What outcome is likely if 2 negative phenotypes are tested during antibody exclusion?

Must yield at least one positive result. Signup and view all the answers

Which component is primarily involved in intravascular complement-mediated hemolysis?

IgM antibodies Signup and view all the answers

What is a major advantage of using Column Agglutination Technology (CAT) in antibody detection?

No washing of samples is necessary Signup and view all the answers

What is the primary purpose of administering fresh frozen plasma?

To prevent microvasculature bleeding due to loss of clotting factors Signup and view all the answers

What is the purpose of the Sephadex gel matrix in the Diamed-ID Micro Typing System?

To trap free cells during centrifugation Signup and view all the answers

Which of the following best describes the requirement for matching in red cell transfusions?

Both antigen and plasma groups must be matched Signup and view all the answers

Which of the following is NOT a component of the solid-phase technology for antibody detection?

Direct centrifugation of serum mixture Signup and view all the answers

Which of the following is a disadvantage of Column Agglutination Technology?

High cost of consumables Signup and view all the answers

What does 'goodness of fit' refer to in the context of antibody-antigen interactions?

The specific shape and charge compatibility of an antibody and epitope Signup and view all the answers

What does the BioVue System use to capture agglutinates during antibody detection?

A slurry of glass beads Signup and view all the answers

Which factor can cause adverse reactions in platelet transfusions?

Incompatible plasma groups Signup and view all the answers

Which component is necessary for the reverse blood grouping process?

Using known red cell types across two groups Signup and view all the answers

Column Agglutination Technology is well known for which of the following characteristics?

Automatic processing and standardization Signup and view all the answers

What determines the difference between affinity and avidity concerning antibodies?

Affinity refers to a single antibody's strength, while avidity is the cumulative strength of multiple antibodies Signup and view all the answers

Which component of Column Agglutination Technology allows reactions to be visualized effectively?

AHG impregnated cards Signup and view all the answers

What is the primary objective of the solid phase technique in antibody detection?

To capture IgG antibodies onto a solid surface Signup and view all the answers

What is a major consequence of mismatching platelet antigens during transfusion?

Reduced efficacy of the transfusion and potential for reactions Signup and view all the answers

How is the serum/cell mixture treated in the Column Agglutination Technology procedure?

Incubated at 37°C followed by centrifugation Signup and view all the answers

What role do hydrophobic and electrostatic forces play in antibody-antigen interactions?

They contribute to the physical and chemical complementariness required for binding Signup and view all the answers

In antibody screening, what is essential for confirming the presence of antibodies?

Employing multiple reagent screening cells expressing various antigens Signup and view all the answers

Which of the following antigen detection methods does not require the washing step?

Column agglutination technology Signup and view all the answers

Study Notes

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.

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.

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Description

Test your knowledge on blood transfusion protocols and agglutination tests including solid-phase technology and sample acceptance criteria. Understand the critical aspects of antibody screening and compatibility in transfusions. This quiz covers essential concepts for healthcare professionals involved in blood transfusion management.