Blood Group Antibodies

Question 1

Warm reacting IgG

R D K K M N S

Answer 1

Rh, Duffy, Kidd, Kell, MNS’

Question 2

Reacts with an antigen on the patient’s own cells

Answer 2

Autoantibody

Question 3

Reacts with a foreign antigen not present on the patient’s own erythrocytes

Answer 3

Alloantibody

Question 4

Antigenic stimulus is unknown; occurs without exposure to antigens

Answer 4

Natural occurring antibodies

Question 5

Individual exposed to biochemical structures similar to A or B antigens in the environment (bacteria, pollen, plants)

Answer 5

Non-RBC stimulated antibody

Question 6

Produced after exposure to foreign erythrocyte antigens through transfusion or pregnancy

Answer 6

Immune antibodies

Question 7

Naturally occurring antibodies characteristics

Answer 7

IgM, React at 4-22°C

Question 8

Immune antibodies characteristics

Answer 8

IgG, React at 37°C

Question 9

Clinical significance of IgG

Answer 9

Causes HTR (hemolytic transfusion reaction) and HDN (hemolytic disease of the newborn)

Question 10

Red cells from homozygous individuals possess more antigens per red cell than those from heterozygous individuals

Answer 10

Dosage effect

Question 11

pH for antigen-antibody reaction

Answer 11

6.5 to 7.5

Question 12

Temperature for IgM and IgG antibodies

Answer 12

IgM reacts at room temperature; IgG reacts at body temperature

Question 13

Biphasic antibody

Answer 13

auto-anti-P

Question 14

Over centrifugation effect

Answer 14

Causes false positive results

Question 15

Under centrifugation effect

Answer 15

Causes false negative results

Question 16

Reagents that enhance IgG antibody detection by reducing zeta potential, promoting antibody uptake, or direct agglutination

Answer 16

Enhancement medium

Question 17

Increased concentration promotes rouleaux formation in enhancement medium

Answer 17

Bovine serum albumin (22%)

Question 18

Removes water molecules, enhances antibody detection by reducing surface tension and promoting closer interaction between cells

Answer 18

Polyethylene Glycol (PEG)

Question 19

Polyethylene Glycol (PEG) incubation

Answer 19

Incubate for 10-30 minutes without centrifuge to avoid false positive results

Question 20

More effective than albumin or LISS for detecting weak antibodies in enhancement medium

Answer 20

Polyethylene Glycol (PEG) effectiveness

Question 21

Enhancement medium used in antibody detection

Answer 21

Protamine

Question 22

Enhancement medium used in antibody detection

Answer 22

Polyvinylpyrrolidone (PVP)

Question 23

Low Ionic Strength Solution (LISS) component

Answer 23

Contains 0.2% sodium chloride; reduces ionic strength and zeta potential, allowing more efficient antibody-antigen reactions

Question 24

LISS incubation time

Answer 24

5-10 minutes

Question 25

LISS disadvantage

Answer 25

Prone to false positives

Question 26

Use of enzymes in blood testing

Answer 26

Target sialic acid and protein molecules to enhance or destroy specific antigens

Question 27

Enzymes that enhance antigen reactions

Answer 27

Papain, Ficin, Trypsin, Bromelain

Question 28

Enzymes that enhance antigens

Answer 28

Rh, Kidd, P1, Lewis, I antigens

Question 29

Enzymes that destroy antigens

Answer 29

Fya, Fyb, M, N, S, Duffy, MNSS

Question 30

Antihuman Globulin Reagent (AHG)

Answer 30

Used in Coombs' test to detect antibodies and complement proteins attached to RBCs

Question 31

Coombs' test discovery year

Answer 31

1945 by Coombs, Mourant, and Race

Question 32

Kell antigen discovery

Answer 32

Kell was the first antigen discovered using Coombs' test

Question 33

Detects in vivo sensitization of RBCs with IgG/complement components

Answer 33

Direct AHG

Question 34

Direct AHG procedure

Answer 34

Washed RBC + AHG reagent; does not require washing

Question 35

Detects in vitro sensitization of RBCs

Answer 35

Indirect AHG

Question 36

Uses of Indirect AHG

Answer 36

Antibody detection, Antibody identification, Antibody titration, Red cell phenotyping, Crossmatching

Question 37

Indirect AHG procedure (patient's red cells)

Answer 37

Incubate with anti-sera, wash 3x, add AHG reagent, check cells

Question 38

Contains antibody to human IgG and to the C3d component of human complement

Answer 38

Polyspecific AHG

Question 39

Contains only one antibody specificity: anti-IgG or antibody to specific components of complement (C3b or C3d)

Answer 39

Monospecific AHG

Question 40

Mixture of antibodies from different plasma cell clones recognizing different epitopes or same epitope with different affinities

Answer 40

Polyclonal AHG

Question 41

Derived from one clone of plasma cells, recognizes a single epitope

Answer 41

Monoclonal AHG

Question 42

Red cells with attached antibody added to AHG negative result to confirm test validity

Answer 42

Check Cells

Question 43

Prompt

Answer 43

Answer

Question 44

Detects 100 to 500 IgG molecules per RBC and 400 to 1,100 molecules of C3d per RBC

Answer 44

DAT sensitivity

Question 45

100 to 200 IgG or C3 molecules on the cell for a positive reaction

Answer 45

IAT sensitivity

Question 46

Antibody-mediated clumping of particles expressing antigen on the surface

Answer 46

Agglutination

Question 47

Rupture of red cells with release of intracellular hemoglobin

Answer 47

Hemolysis

Question 48

Formation of an insoluble complex when soluble antigen reacts with soluble antibody

Answer 48

Precipitation and flocculation