Basic Immunohematology – Detailed Study Notes

A comprehensive set of vocabulary flashcards covering key terms and concepts in Immunohematology.

Antigens

Structures on RBC surface that can trigger immune response.

Antibodies

Proteins (immunoglobulins) that bind specific antigens.

Binding specificity

Highly specific binding mechanism likened to a lock-and-key.

Sensitization

The binding stage where antibodies attach to antigens.

Agglutination

Visible clumping of RBCs.

IgM

Immunoglobulin that causes large, immediate agglutination; reacts cold.

IgG

Immunoglobulin that requires AHG to detect; reacts warm.

Temperature effect on IgM

IgM reacts at lower temperatures, typically cold.

Temperature effect on IgG

IgG reacts optimally at 37°C.

pH optimal range for reactions

Optimal pH for reactions is around 6.5–7.5.

Incubation time

Time required for antibody binding.

Antigen density effect

Dosage effect where homozygous antigens are stronger.

Zeta potential

Negative charge between RBCs affecting agglutination.

Hemolysis

Destruction of RBCs, can be a positive reaction.

Sensitization without agglutination

IgG coating of RBCs without visible clumping.

Complement activation

Leads to the destruction of RBCs.

Anti-human globulin (AHG/Coombs reagent)

Detects IgG or complement on RBCs.

Anti-A

Reagent used for ABO blood typing.

Anti-B

Reagent used for ABO blood typing.

Anti-D

Reagent used for Rh blood typing.

Screening cells

Cells used to detect unexpected antibodies.

Panel cells

Cells used for antibody identification in blood banking.

Check cells

Cells that validate negative AHG tests.

LISS (Low Ionic Strength Solution)

Potentiator that speeds up antibody binding.

PEG (Polyethylene Glycol)

Concentrates antibodies and increases sensitivity.

Albumin

Reduces zeta potential in blood banking.

Enzymes (ficin, papain)

Enhance some antigens and destroy others.

4+ Reaction Strength

Solid agglutination.

3+ Reaction Strength

Several large clumps.

2+ Reaction Strength

Medium clumps with clear background.

1+ Reaction Strength

Small clumps with turbid background.

W+ Reaction Strength

Barely visible agglutination.

0 Reaction Strength

No reaction.

High-Yield Point on IgM

IgM = immediate agglutination; reacts cold.

High-Yield Point on IgG

IgG = requires AHG; reacts warm.

AHG reaction detection

AHG detects sensitization, not visible agglutination.

Positive check cells necessity

Check cells must always yield a positive result.

Positive hemolysis reaction

Hemolysis can indicate a positive reaction.

Most sensitive potentiator

PEG is the most sensitive potentiator.

Lock-and-key model

A model that describes the specificity of antigen-antibody binding.

Colloidal (colloidal gold) test

Method used to visualize reactions in blood typing.

Direct Coombs test

Test to detect antibodies that are bound to the surface of red blood cells.

Indirect Coombs test

Test to detect free antibodies in the patient’s serum.

Universal donor blood type

O negative type blood, compatible with all Rh factors.

Universal recipient blood type

AB positive type blood, can receive from all blood types.

Apheresis

Procedure to separate blood components.

Autologous transfusion

Transfusion using the patient's own blood.

Allogeneic transfusion

Transfusion using blood from a donor.

Hemoglobin F

Fetal hemoglobin that has a higher affinity for oxygen.

Erythrocyte sedimentation rate (ESR)

Test that measures the settling of red blood cells in a tube.

Type and crossmatch

Procedure to ensure compatibility before transfusion.

Blood group antigens

Specific molecules present on the surface of RBCs that define blood types.

Transfusion reactions

Adverse effects that can occur after a blood transfusion.

Hematopoiesis

The process of blood cell formation.

B-cells

Lymphocytes responsible for producing antibodies.

T-cells

Lymphocytes involved in cell-mediated immunity.

Memory cells

Long-lived B or T cells that remember pathogens.

Plasma

Liquid component of blood containing antibodies.

Serum

Fluid obtained after blood has clotted that contains antibodies.

Immunization

Process of stimulating the immune system to develop protection.

Vaccines

Substances introduced into the body to stimulate an immune response.

Immunoglobulin classes

Five classes: IgG, IgA, IgM, IgE, IgD.

Neutralization

Antibodies bind to pathogens, preventing entry into cells.

Opsonization

Tagging of pathogens for destruction by the immune system.

Monoclonal antibodies

Antibodies produced from a single clone of cells.

Polyclonal antibodies

Antibodies produced from multiple clones.

Affinity maturation

Process where B cells enhance antibody affinity for antigens.

Cytokines

Signaling proteins that regulate immune responses.

Adaptive immunity

Immunity that develops over time with exposure to antigens.

Innate immunity

Immediate, non-specific defense against pathogens.

Helper T cells

T cells that assist in the activation of B cells and cytotoxic T cells.

Cytotoxic T cells

T cells that kill infected or cancerous cells.

Immunocompromised

Individuals with weakened immune systems.

Transfusion-transmitted infections

Infections that can be transmitted through blood transfusion.

Blood safety regulations

Regulations ensuring the safety of blood products.

ABO blood group system

Classification of human blood based on antigens.