Fundamentals of Immunohema

Question 1

most common forms of blood group antigens

Answer 1

glycoproteins
glycolipids
proteins

Question 2

antibody found in individual’s serum who were previously exposed to rbc antigens. usually IgG

Answer 2

rbc immune antibody

Question 3

antibody found in individual’s serum who have never been previously exposed to rbc antigens. usually IgM

Answer 3

non-rbc immune antibody

Question 4

antibody that decreases the red cell survival. destroys rbc in vivo.

Answer 4

clinically significant antibody

Question 5

antibody produced in response to foreign antigens

Answer 5

alloantibody

Question 6

antibody produced in response to self-antigen

Answer 6

autoantibody

Question 7

characteristics of IgG antibodies

Answer 7

monomer
warm, reacts at 37C
cross placental barrier
poor to good C' activators
usually clinically significant rbc immune antibody

Question 8

characteristics of IgM antibodies

Answer 8

pentamer
cold, reacts at 4-10C
cannot cross placental barrier
good C' activators
usually not clinically significant, non rbc immune

Question 9

very clinically significant IgM antibodies

Answer 9

ABO antibodies

Question 10

antibody normally seen in tears, saliva and other secretions

Answer 10

IgA

Question 11

this attaches to basophils or mast cell to facilitate histamine release

Answer 11

IgE

Question 12

theories that keep in vivo rbc distant from each other

Answer 12

waters of hydration

electrostatic charges/zeta potential

Question 13

antibody coating rbc without agglutination, antibody-antigen attachment

Answer 13

sensitization

Question 14

complement mediated lysis of rbc

Answer 14

rbc hemolysis

Question 15

antibody mediated clumping of rbc

Answer 15

agglutination

Question 16

this reaction isn’t seen at IS, RT or LISS phases

Answer 16

sensitization

Question 17

this requires use of an antihuman globulin reagent in direct or indirect AT

Answer 17

sensitization

Question 18

color of AHG reagent

Answer 18

green

Question 19

what is formed when complement is activated in hemolysis

Answer 19

MAC(C5b-9)

Question 20

appearance of supernatant in hemolysis

Answer 20

clear and red

Question 21

why do antibodies against Rh antigens do not bind complement

Answer 21

low level of Rh antibodies on rbc surfaces

Question 22

this is the end product of complement

Answer 22

cell lysis

Question 23

two processes of agglutination reaction

Answer 23

sensitization

lattice formation

Question 24

refers to corresponding antigenic site

Answer 24

epitope

Question 25

refers to corresponding antibody site

Answer 25

paratope

Question 26

weak non-specific intermolecular forces involved in sensitization

Answer 26

electrostatic forces hydrogen bonds hydrophobic forces van der Waals

Question 27

major binding force

Answer 27

hydrophobic bonds

Question 28

Law of Mass Action

Answer 28

antigen and antibody complexing is reversible

Question 29

antibody excess

Answer 29

prozone

Question 30

antigen excess

Answer 30

postzone

Question 31

this illustrate the effect of antigen and antibody mass on lattice formation

Answer 31

heildelberg phenomenon

Question 32

factors affecting stage 1 of agglutination

Answer 32

temperature pH incubation time ionic strength

Question 33

IgM antibodies bond better at low temp (4-10C) due to ____

Answer 33

carbohydrate nature of antigens

Question 34

IgG antibodies bond better at 37C due to ____

Answer 34

protein nature of Rh antigens

Question 35

optimal pH in agglutination

Answer 35

6.5-7.5

Question 36

incubation time in saline systems

Answer 36

60-120mins at 37C

Question 37

LISS and BSA reduce incubation time to ___

Answer 37

LISS : 10-15mins | BSA : 3-60mins at 37C

Question 38

the lower the ionic strength, _____

Answer 38

higher rate of Ag-Ab association

Question 39

factors affecting stage 2 of agglutination

Answer 39

``` size of immunoglobulin number of binding sites location and number of antigenic determinants centrifugation zeta potential waters of hydration ```

Question 40

IgG and IgM both require AHG to form lattice formation (t/f)

Answer 40

false. IgG only

Question 41

no. of IgG binding site

Answer 41

2

Question 42

no. of IgM binding site

Answer 42

10

Question 43

this causes false negative result

Answer 43

undercentrifugation

Question 44

this causes false positive result

Answer 44

overcentrifugation

Question 45

this acts as an insulation bubble around rbc

Answer 45

waters of hydration

Question 46

common enhancement media / potentiators used

Answer 46

LISS, albumin, AHG

Question 47

this crosslinks sensitized cells causing visible agglutination

Answer 47

AHG

Question 48

this causes agglutination by adjusting zeta potential between RBCs

Answer 48

22% albumin

Question 49

ths uses low ionic strength to take up antibody more rapidly

Answer 49

LISS

Question 50

grading of agglutination reaction strength

Answer 50

Neg-4+

Question 51

this typing detects antigen in RBC

Answer 51

forward typing

Question 52

this typing deetects antibody in RBC

Answer 52

reverse/backward typing

Question 53

cause of rouleaux formation

Answer 53

increased proteins (false positive)

Question 54

presence of two cell populations. results of mixture of clumping cells and free cells

Answer 54

mixed field agglutination