1-INTRODUCTION TO IMMUNOHEMATOLOGY Flashcards
(182 cards)
1
Q
What is the foundation of immunohematology testing used to identify blood types detect antibodies and ensure compatibility for transfusion
A
Antigen-antibody reactions
2
Q
What is the specific combination of antigens and antibodies with each other called
A
Antigen-Antibody reaction
3
Q
What are antigen-antibody reactions that occur in vitro called
A
Serological reactions
4
Q
What is the reversible binding process between antigen and antibody that follows a specific principle
A
Antigen-Antibody reaction
5
Q
What principle explains how antigen and antibody interact to form immune complexes depending on their concentration
A
Law of Mass Action
6
Q
What factor determines the amount and stability of immune complex formation
A
Association constant
7
Q
What is the forward process of antigen and antibody binding called
A
Forward reaction
8
Q
Why are antigen-antibody reactions reversible
A
Non-covalent bonds
9
Q
What type of bonds are exclusively involved in antigen-antibody binding sites and epitopes
A
Non-covalent bonds
10
Q
How do non-covalent bonds compare to covalent bonds in strength
A
Weaker than covalent bonds
11
Q
What factor influences the rate at which antigen-antibody complexes dissociate
A
Dissociation constant
12
Q
Why is reversibility important in antigen-antibody reactions
A
Immune system regulation + antibody screening + diagnostic test adjustments
13
Q
What intermolecular binding force results from attraction between oppositely charged ionic groups of protein side chains
A
Electrostatic forces
14
Q
What non-covalent bond involves a hydrogen atom bridging two electronegative atoms playing a major role in antigen recognition
A
Hydrogen bonding
15
Q
What non-covalent bond occurs between non-polar amino acid residues causing water repulsion that strengthens antigen-antibody interaction
A
Hydrophobic bonding
16
Q
What weak transient interaction due to fluctuating electron cloud contributes to fine-tuning antigen epitope and antibody paratope binding
A
Van der Waals forces
17
Q
What term means the most noticeable features of antigen-antibody reactions
A
Salient features
18
Q
What is the ability of an individual antibody combining site to react with only one antigenic determinant called
A
Specificity
19
Q
How does each antibody bind to a specific antigen
A
Lock and key mechanism
20
Q
What part of antigen is recognized by an antibody
A
Epitope
21
Q
What part of antibody binds to the antigen
A
Paratope
22
Q
Why is the antigen-antibody reaction reversible
A
Because non-covalent bonds are weak and temporary allowing dissociation under certain conditions
23
Q
What non-covalent bonds are involved in antigen-antibody reactions
A
Electrostatic forces + Hydrogen bonding + Hydrophobic bonding + Van der Waals forces
24
Q
Which non-covalent bond is stronger in stabilizing antigen-antibody interactions
A
Hydrophobic bonding
25
How do van der Waals forces help stabilize immune complexes
By improving the fit between antigen epitope and antibody paratope
26
What drives immune complex formation in the forward reaction
Association constant
27
What is formed when antigen and antibody combine
Immune complex
28
What do antigen-antibody reactions help identify and ensure in transfusion
Blood types + antibodies + compatibility
29
What term describes the highly specific reaction where an antigen reacts only with antibodies produced by itself or closely related antigens
Specificity
30
What term describes the molecular shape recognition by an antibody of an antigen
Specificity
31
What analogy describes the relationship where the antibody binding site shape matches the antigen epitope shape
Lock and Key
32
What is the basis of many diagnostic tests for detecting antigen or antibody in vitro
Antigen-antibody reactions
33
What forms the basis of immunity against microbial diseases in vivo
Antigen-antibody reactions
34
What is formed from the integral binding of an antibody to a soluble antigen
Immune complex
35
What symbol denotes the reversible nature of antigen-antibody complex reactions
⇄
36
What is the part of antigen that combines with antibody called
Epitope
37
What is the part of antibody that recognizes the epitope called
Paratope
38
What is another name for the antibody binding site
Paratope
39
What refers to how strongly an antibody attaches to an antigen
Binding force
40
What type of bonds are involved in antigen-antibody binding force
Non-covalent bonds
41
What weak attraction occurs between atoms in antigen-antibody binding
Hydrogen bonds
42
What attraction occurs between opposite charges in antigen-antibody binding
Electrostatic forces
43
What weak interaction occurs when molecules are close in antigen-antibody binding
Van der Waals forces
44
What interaction involves nonpolar molecules sticking together in antigen-antibody binding
Hydrophobic interactions
45
What term describes the combined strength of a non-covalent interaction between a single antibody binding site and a single epitope
Affinity
46
What region of antibody binds antigenic determinant during affinity interaction
Complementarity determining region (CDR)
47
What happens to low affinity antibodies in terms of antigen binding
Bind weakly + dissociate readily
48
What happens to high affinity antibodies in terms of antigen binding
Bind tightly + remain bound longer
49
What constant describes the rate that helps the binding of antigen and antibody in forward reaction
Association constant (k1)
50
What constant influences the reverse reaction or dissociation of antigen-antibody complex
Dissociation constant (k₋₁)
51
What term describes the overall strength of the bond after formation of antigen-antibody complexes
Avidity
52
What term denotes the total binding strength of an antibody at all binding sites
Avidity
53
What is another name for avidity referring to functional binding capacity
Functional affinity
54
What antibody structure enables high avidity despite low affinity
Pentameric IgM structure
55
What term describes an antigen with many types of antigenic determinants
Multivalent antigen
56
What term describes antibodies having multiple binding sites
Multivalent antibodies
57
What increases the probability of antigen binding to multiple antibody sites
Multiple interactions of multivalent antigen and antibody
58
What term describes an antiserum reacting with a similar but different antigen
Cross reaction
59
What is the antigen called that produces a cross reaction
Cross reactive antigen
60
How does the strength of antibody binding compare between its own antigen and cross reactive antigen
Stronger to own antigen
61
What occurs when an antibody raised against one antigen also reacts with a different but similar antigen
Cross reaction
62
What causes cross reaction due to shared shape between unrelated antigens
Similar epitope shape
63
What happens when an antibody binds both its specific antigen and a similar antigen
Cross reaction
64
What term describes an antibody reacting with multiple antigens despite being formed against one
Cross reaction
65
In antibody identification what example shows cross reaction by anti-K antibody
Anti-K binding multiple antigens
66
How does the affinity of antibody compare between original and cross-reacting epitopes
Higher affinity to original epitope
67
What are the different ways antibodies react with specific antigens in vitro
Types of antigen-antibody reaction
68
Name the most common antigen-antibody reactions used in immunohematology
Agglutination + Hemolysis
69
What is the visible clumping of particulate antigens caused by specific antibody interaction
Agglutination
70
What is agglutination using red blood cells called
Hemagglutination
71
What determines the specificity of red blood cell antigen or antibody in routine blood banking
Hemagglutination
72
When does agglutination happen optimally
When antigen and antibody react in equal proportion
73
What forms a lattice network bridging antibodies and cells carrying antigens
Antibodies
74
What type of antigen-antibody reaction takes place on the surface of particles producing visible clumps
Agglutination
75
What is the role of red blood cells in hemagglutination
Carrier particles for antigens
76
What is direct agglutination
Agglutination of naturally occurring antigens on cell surfaces by corresponding antibodies
77
What is the characteristic of direct agglutination regarding enhancement reagents
Occurs naturally without enhancement reagent
78
What is tube agglutination
Serial dilution of serum with constant antigen suspension incubated to observe agglutination
79
What is slide agglutination
Basic agglutination test performed on a slide with antigen and antiserum suspension
80
What is the principle behind the antiglobulin test
Antihuman globulins bind to human IgG or complement free or attached to RBCs
81
What is another name for the antiglobulin test
Coombs test
82
What type of antibodies directly agglutinate RBCs suspended in saline
IgM
83
Why is antiglobulin reagent needed for IgG detection in agglutination
IgG is too small to sensitize RBCs directly
84
Why is antiglobulin test considered direct agglutination
Detects naturally occurring antigen-antibody complexes without modifying antigens
85
What is passive agglutination
Agglutination involving artificially attached antigens or antibodies to carrier particles
86
What is required for passive agglutination to produce visible clumps
Enhancement reagent
87
How does passive agglutination differ from antiglobulin test
Modifies antigens on carrier particles unlike antiglobulin test
88
What types of carrier particles are used in passive agglutination
RBC + Latex particles + Bentonite + Polystyrene coated RBCs
89
What clinical condition is diagnosed using passive agglutination test
Rheumatoid arthritis
90
What type of agglutination requires reagents to improve sensitivity without using carrier particles
Passive agglutination
91
What is artificially attached to carrier particles to enhance agglutination in passive agglutination
Soluble antigens
92
What are the two distinct stages of antibody-mediated agglutination
Sensitization + Lattice formation
93
What happens in the first stage of agglutination involving physical attachment of antibody to antigenic determinant
Sensitization
94
What may occur after sensitization involving binding or fixing of complement components
Complement fixation
95
What causes visible clumping in the second stage of agglutination
Cross-linking of sensitized cells by antibody bridges
96
What is the aim of blood group serology in agglutination testing
Maximum sensitivity without loss of specificity
97
What occurs during the sensitization stage of red cell agglutination
Antibody binds antigen on red cell membrane
98
What type of reaction is required for the sensitization stage
Immunologic reaction between antigen and antibody
99
What is not produced during the sensitization stage
Visible agglutination
100
How is the sensitization stage described in terms of speed and reversibility
Rapid and reversible
101
Which factor affects the first stage of agglutination related to temperature
Temperature
102
At what temperature do most clinically relevant IgG antibodies react optimally
37 degrees Celsius
103
At what temperature do cold antibodies react best
4 degrees Celsius or lower
104
What factor affects the time needed to reach equilibrium in antigen-antibody binding
Incubation time
105
What happens if incubation time is too short during agglutination testing
Weak and undetected antibody binding
106
What happens if incubation time is too long during agglutination testing
Antibody dissociation causing false negative results
107
What is the optimal pH range for heme agglutination
Around 7.0
108
At what pH does anti-D react best
6.5 to 7.0
109
At what pH does anti-M react best
5.5
110
What factor affects electrostatic interactions between antigens and antibodies
Ionic strength
111
What charge do red blood cells carry due to sialic acid residues
Net negative charge
112
What forms around RBCs in electrolyte solution preventing spontaneous aggregation
Diffused double layer or ionic clouds
113
What must antibodies overcome to bind antigens on RBCs
Electrostatic repulsion
114
What solution is commonly used to reduce ionic strength and enhance antigen-antibody interaction
Low ionic strength solution (LISS)
115
What is the second stage of antibody-mediated agglutination involving cross-linking of sensitized RBCs
Lattice formation
116
What factor describes differences in electrostatic charges at RBC surface affecting agglutination
Zeta potential
117
What effect does high positive Zeta potential have on RBCs
Strong repulsion keeping RBCs apart preventing agglutination
118
What effect does low Zeta potential have on RBCs
Weak repulsion allowing RBC clumping
119
Which antibody can bridge RBCs despite Zeta potential due to its size and pentameric structure
IgM
120
Why does IgG struggle to form a lattice due to Zeta potential
Small size and short lifespan limiting overcoming repulsion
121
How can IgG overcome Zeta potential repulsion to cause agglutination
Reducing Zeta potential with reagents
122
Name reagents used to reduce Zeta potential and enhance agglutination
Albumin + Proteolytic enzymes + PEG + AHG
123
What is the ideal condition for antigen and antibody concentrations during agglutination
Equivalent amounts for optimal reaction
124
What term describes the condition where antibody and antigen concentrations are optimal for visible agglutination
Zone of equivalence
125
What results from antibody excess causing unbound antibodies due to insufficient antigen
Prozone
126
What results from antigen excess causing unbound antigen due to insufficient antibodies
Post zone
127
What process enhances lattice formation by reducing reaction time and bringing reactants closer
Centrifugation
128
How does centrifugation affect Zeta potential during agglutination
Can overcome Zeta potential
129
What type of antibodies activate complement cascade causing lysis of red blood cells
Hemolysins
130
What term describes the lysis of red blood cells by complement activation
Hemolysis
131
What type of sample is required to detect hemolysis in vitro
Fresh serum samples
132
Why is hemolysis not observed in plasma samples
Plasma lacks complement activation
133
What causes pinkish or reddish supernatant during reverse ABO typing
Hemolysis releasing intracellular fluid
134
What causes membrane damage leading to hemolysis in antigen-antibody reactions
Membrane attack complex from complement activation
135
What is tested when red cell antigens are unknown using patient or donor samples
Antigen identity
136
What source contains known red blood cell antibodies used to identify unknown antigens
Commercial antisera
137
What source contains unknown antibodies tested with known antigen sources
Patient or donor serum or plasma
138
What is used in reverse ABO typing to identify antibodies in patient serum
Reagent red cells with known antigens
139
What is used in forward ABO typing to identify antigens on patient or donor red cells
Commercial antisera with known antibodies
140
Where are antigens attached in blood typing samples
Red cells
141
Where are antibodies attached in blood typing samples
Plasma or serum
142
What test identifies blood group and Rh status
ABO and Rh typing
143
What are the two components of ABO typing
Forward typing + Reverse typing
144
What test detects unexpected antibodies in blood donors and recipients
Antibody screening
145
What test detects in vitro sensitization of red blood cells
Direct antiglobulin test (DAT)
146
What test detects in vivo sensitization of red blood cells
Indirect antiglobulin test (IAT)
147
What test ensures compatibility between donor and recipient blood
Crossmatching
148
What is performed if antibody screening is positive to determine antibody specificity
Antibody identification
149
Why can crossmatching be compatible despite positive antibody screening
Donor lacks corresponding antigen for patient antibody
150
Is it safe to transfuse blood when antibody screening is positive
Yes with monitoring during transfusion
151
What field focuses on antigen-antibody interactions in blood transfusion and immune blood disorders
Immunohematology
152
What reagents are crucial for detecting blood group antigens and antibodies to ensure transfusion safety
Immunohematology reagents
153
What laboratory tests use immunohematology reagents
Blood typing + Antibody screening + Crossmatching
154
What transfusion complications are prevented by immunohematology testing
Transfusion reactions + Hemolytic disease of the newborn (HDN)
155
What is the required frequency of testing for blood grouping serum
Each day of use
156
What is the required frequency of testing for reverse grouping cells A cells and B cells
Each day of use
157
What is the required frequency of testing for antibody screening cells
Each day of use
158
What is the required frequency of testing for antibody identification cells
Each day of use
159
What parameter requires no turbidity precipitate particles or gel formation by visual inspection
Appearance
160
How often should appearance of reagents be checked
Each day
161
What parameter requires positive reaction with red cells having corresponding antigen and no reaction with negative control macroscopic agglutination
Specificity
162
How often should specificity of reagents be checked
Daily and each new lot or batch
163
What parameter requires 50 percent red cell suspension in homologous serum or normal saline using slide test at room temperature
Avidity
164
What is the required time for avidity test for anti-A anti-B and anti-AB with A1 and or B cells
10 seconds
165
What is the required time for avidity test with A2 and A2B cells
20 seconds
166
How often should avidity of reagents be checked
Daily and each new lot or batch
167
What parameter requires no immune hemolysis rouleaux formation or prozone
Reactivity
168
How often should reactivity of reagents be checked
Each new lot or batch
169
What parameter requires undiluted serum to give strong reactions in saline tube test using 3 percent red cell suspensions at room temperature
Potency
170
How often should potency of reagents be checked
Each new lot or batch
171
What agency regulates blood bank reagents as biological products and in vitro diagnostic medical devices
US Food and Drug Administration
172
What does the FDA establish for use in blood banks and transfusion services before assigning a license to a commercial reagent
Minimum standards
173
What must manufacturers meet to receive a product license number for blood bank reagents
Minimum standards for specificity and potency
174
What is displayed on the product label of licensed blood bank reagents
Product license number
175
What information is found on reagent labels along with the product license number
Expiration date and manufacturing date
176
What must be checked during quality control of reagents
License number or lot number and expiration date
177
What is not allowed to be used in procedures unless it passes quality control in rare cases
Expired reagent
178
When can expired rare antisera or reagent red cell be used
If it passes quality control
179
How often is quality control recommended for anti sera and manually prepared red cells
Every day or every shift
180
Why is it recommended to check red cell suspension every day or shift
To detect cross contamination or hemolysis
181
How often should antibody screening cells and antibody identification cells be checked
Every day and every shift
182
What are the quality requirements for ABO reagent anti-A anti-B and anti-AB
Appearance + Specificity + Avidity + Reactivity + Potency
