BLOOD BANK METHODS

Question 1

The traditional method uses what reaction chamber?

Answer 1

Tube

Question 2

The gel method uses what reaction chamber?

Answer 2

Microtube card

Question 3

The solid phase method uses what reaction chamber?

Answer 3

Microplate wells

Question 4

Reaction patterns of
Traditional method (tube):
Gel method (microtube card):
Solid phase method (microplate wells):

Answer 4

Reaction patterns of
Traditional method (tube): Hemagglutination
Gel method (microtube card): Hemagglutination
Solid phase method (microplate wells): Immune adherence

Question 5

Reaction matrix of gel method:

Answer 5

Dextran acrylamide gel

Question 6

Reaction matrix of solid phase method:

Answer 6

Modified polystyrene wells

Question 7

Which blood bank method does not require washing?

Answer 7

Gel method

Question 8

What us the purpose of the Gel?

Answer 8

serves as a filter to trap agglutinated RBCs

Question 9

Developed in Europe by Dr. Yves Lapierre; uses dextran-acrylamide gel that contains pre dispensed reagents:

Answer 9

Column Agglutination Technology (CAT)/ Gel Test Method

Question 10

Capture immunoassays are available to detect antibodies to RBCs, platelets, and CMV; it uses microplate wells coated with the target antigen; plasma or serum is then added as well as LISS incubated at 37C then washed; Finally, indicator red cells (anti-IgG-coated RBCs) are added and centrifuged

Answer 10

Solid Phase Red Cell Adherence (SPRCA) by Immucor

Question 11

Positive and negative results in SPRCA

Positive =
Negative =

Answer 11

Positive and negative results in SPRCA

Positive = Diffuse pattern/ RBC monolayer
Negative = RBC pellet at the bottom

Question 12

Uses microplate wells that are coated with Protein A:

Answer 12

Solid Phase Protein A Technology by BioRad

Question 13

Formats inSolid Phase Protein A Technology by BioRad\

Erytype S -
Solidscreen II -

Answer 13

Formats inSolid Phase Protein A Technology by BioRad\

Erytype S - for ABO, Rh, and Kell typing
Solidscreen II - for antiglobulin testing

Question 14

Factors that influence agglutination reactions:

Answer 14

1. High speed centrifugation
2. Effect of antigen-antibody ratio
3. Dosage
4. Effect of pH
5. Effect of temperature
6. Effect of immunoglobulin type
7. Effect of enhancement media and potentiators

Question 15

Simplest and most common technique to enhance agglutination:

Answer 15

High speed centrifugation

Question 16

Prozone (Ab excess) and Postzone (Ag excess) reactions will lead to _______ results

Answer 16

FALSE-NEGATIVE

Question 17

Remedies

Prozone =
Postzone =

Answer 17

Remedies

Prozone = serum dilution techniques
Postzone = increase serum to cell ratio

Question 18

Strength of agglutination reaction of heterozygous alleles

Answer 18

weak agglutination upon testing (1+ or 2+ or WK)

Question 19

Strength of agglutination reaction of homozygous alleles

Answer 19

stronger agglutination upon testing (4+ or 3+)

Question 20

Blood groups that shows dosage effect:

Answer 20

• Duffy
• MNSs
• Kidd
• Rh (C, c, E, e)
• Lutheran

Question 21

Ideal pH for agglutination reactions:

Answer 21

pH 6.5 or 7.5

Question 22

Which immunoglobulin reacts best at cold temperature (4-22C)

Answer 22

IgM (cold-reactive)

Question 23

Which immunoglobulin reacts best at warm temperature (37C)

Answer 23

IgG (warm-reactive)

Question 24

Which immunoglobulin is capable of agglutinating red cells even in NSS (0.85%)

Answer 24

IgM (pentamer)

Question 25

Which immunoglobulin cannot agglutinate red cells in saline and requires enhancement media or potentiators?

Answer 25

IgG (monomer)

Question 26

Primarily used to help detect IgG antibodies; aimed at reducing the zeta potential of the red cell membrane

Answer 26

Enhancement media and potentiators

Question 27

It is the expression of the difference in electrostatic potential at the surface of the rec cells and the ionic cloud of positive cations that are attracted to the negative charges on the surface

Answer 27

Zeta potential

Question 28

Enhancement media/ potentiators:

Answer 28

1. Protein Media 2. LISS (low ionic strength solution) 3. Enzymes 4. Anti0Human Globulin (AHG)

Question 29

An enhancement media that increases the dielectric constant, which reduces the zeta potential:

Answer 29

Protein media

Question 30

Examples of protein media:

Answer 30

22% albumin Polyethylene glycol (PEG)

Question 31

An enhancement media that decrease the inonic strength of a reaction medium and so reduce the zeta potential; increase the attraction between positively charged Abs and negatively charged red cells; contain 0.2% NaCl and often used because of increase rate of Ab uptake during sensitization:

Answer 31

LISS (low ionic strength solution)

Question 32

Red cells incubated with LISS incubation temp. and time:

Answer 32

37C for 10-15 minutes

Question 33

Color of LISS solution:

Answer 33

Clear/ colorless

Question 34

Examples of enhancement media enzymes:

Answer 34

- Ficin (fig plant) - Papain (papaya) - Trypsin (pig stomach) - Bromelin (pineapple)

Question 35

Effects of enhancement media enzymes ENHANCES reactivity to: DESTROYS reactivity to:

Answer 35

Effects of enhancement media enzymes ENHANCES reactivity to: Rh, Kidd, Lewis, I, P1 antigens DESTROYS reactivity to: MNS, Duffy, Chido-Rodgers, Xg antigens

Question 36

Cross-links sensitized cells, resulting in visible agglutination; designed to detect cells coated with antibody or complement, or both

Answer 36

Anti-Human Globulin (AHG)

Question 37

Dyes present in AHG:

Answer 37

Patent blue + Tartrazine yellow = GREEN solution AHG color = GREEN

Question 38

Methods for Red Cell Antibody Detection Reaction Phase: IMMEDIATE SPIN (20-30 sec) Detects: Process/Mechanism: Visible result:

Answer 38

Methods for Red Cell Antibody Detection Reaction Phase: IMMEDIATE SPIN (20-30 sec) Detects: IgM Process/Mechanism: Test mixture is centrifuged at Room temperature Visible result: Hemagglutination

Question 39

Methods for Red Cell Antibody Detection Reaction Phase: 37C INCUBATION Detects: Process/Mechanism: Visible result:

Answer 39

Methods for Red Cell Antibody Detection Reaction Phase: 37C INCUBATION Detects: IgG Process/Mechanism: Sensitization of red cells occur; formation of Complement Visible result: Hemolysis (due to C' activation)

Question 40

Methods for Red Cell Antibody Detection Reaction Phase: ANTIGLOBULIN TEST Detects: Process/Mechanism: Visible result:

Answer 40

Methods for Red Cell Antibody Detection Reaction Phase: ANTIGLOBULIN TEST Detects: IgG Process/Mechanism: Contains antibodies that bind the Fc portion of IgG, cross-linking red cells Visible result: Hemagglutination