Deck B

Question 1

Enzymes are protiens that

Answer 1

that increase the rate of a chemical reaction

Question 2

What are the most commonly used enzymes

Answer 2

ficin and papain.

Question 3

4. Less commonly used enzymes are

Answer 3

enzymes are bromelin, pronase, trypsin, and chemotrypsin.

Question 4

Some red cell antigens are _________ by enzymes and others are ___________ by enzymes

Answer 4

Destroyed and enhanced

Question 5

8. Enzyme-treated red blood cells are typically used in two instances:

Answer 5

 If a weakly reactive antibody is present, enzyme-treated red blood cells may be tested in an effort to enhance the reactivity and possibly clarify the reaction pattern or confirm the presence of the antibody.
 Use of enzyme-treated red blood cells can often help differentiate antibodies.

Question 6

9. Enzyme treatment can be performed in two ways:

Answer 6

• The one-step technique: Enzyme is added as an enhancement to the tube containing test plasma and red blood cells and carried through the IAT phase of testing.
• The two-step technique: Requires treatment of the red blood cells with enzyme and washing prior to the addition of patient plasma. This method is often preferred because the enzymes in the one-step technique are added directly to the patient’s plasma and any antibodies present may be damaged.

Question 7

10. ________ red blood cells must be used in tandem with the ____________ red blood cells to identify all antibodies present in a test sample.

Answer 7

Untreated and enzyme-treated

Question 8

Neutralization definition

Answer 8

The inactivation of an antibody by combining it with a soluble form of the corresponding antigen.

Question 9

Neutralization can aid in

Answer 9

2. Inactivation of the antibody can aid in identification of a suspected antibody that does not react with an ideal pattern.

Question 10

Neutralization

Sources of

Answer 10

3. Sources of neutralizing substances include saliva, hydatid cyst fluid, urine, plasma, breast milk, and amniotic fluid.

Question 11

Elution

Answer 11

Frees antibody that is bound to a red blood cell.

Question 12

Uses of an elution

Answer 12

 Identify one or more antibodies attached to the red blood cell membrane.
 Prepare antisera or to detect and identify weakly reactive antibodies.
 Prepare DAT-negative red blood cells for further testing.
 It can be combined with adsorption techniques to remove specific antibodies or antibodies.
 Adsorption and elution techniques can be used to detect a weakly reactive antigen, such as a weak ABO subgroup.

Question 13

4. Methods that are best at releasing cold-reactive antibodies or antibodies that have a broad temperature range of reactivity include:

Answer 13

 Lansteiner and Miller heat elution
 Weiner’s freeze–thaw method
 Lui’s freeze–thaw method and sonication

Question 14

5. Methods better suited for recovering warm-reactive alloantibodies or auto antibodies include

Answer 14

include use of organic solvents such as ether, zylene, methylene chloride, and chloroform or acids such as digitonin, citric, or glycine.

Question 15

6. Procedures that remove antibody but leave the red blood cells intact include

Answer 15

gentle heat, choloroquine, and acid glycine-EDTA methods.

Question 16

7. Preparation of a successful eluate can be influenced by several factors:

Answer 16

 Improper technique
 Inadequate stroma removal
 Insufficient washing of the sensitized red blood cells before eluting the antibody
 Incorrect method of transferring washed red blood cells
 Incorrect procedure used during the wash phase
 Use of saline to prepare eluates

Question 17

Adsorption

Answer 17

1. A technique used to remove an antibody or antibodies from plasma.
2. Done most often to remove autoantibodies from a patient’s specimen in order to see if other antibodies are present in the plasma.
3. Autologous adsorption and allogenic adsorption are the most common types used.

Question 18

Adsorption

Answer 18

Is used to remove a antibody or antibodies from plasma

Done to remove autoantibodies to see if other antibodies are present In the patient plasma

Question 19

4. Autologous adsorption

cannot be used in the previous three months because the patient already has another type of red cell in his system

Answer 19

 The preferred method to remove autoantibodies.
 Cannot be used if the patient has been transfused within the previous 3 months because the patient’s specimen will also contain donor red blood cells.

Question 20

5. Allogenic adsorption

May be used when a patient with a autoantibody has been

Answer 20

Transfused

Question 21

5. Allogenic adsorption

Used either alone or paired with elution techniques to separate mixtures of

Answer 21

antibodies to allow for identification

Question 22

 When choosing red blood cells for adsorption, the red cells that stimulate the most ___________ antibodies are considered.

Answer 22

Clinically significant

Question 23

 Procedure requires a great deal of technical expertise because donor red blood cells adsorb both

Answer 23

autoantibodies and alloantibodies.

Question 24

 Allogenic adsorptions run the risk of not detecting a

Answer 24

clinical significant antibody if a weakly reactive alloantibody is diluted or antibody to a high-frequency antigen is absorbed. Autoantibodies that are only partially absorbed may mimic the reaction pattern of alloantibodies.

Question 25

6. Rabbit erythrocyte stroma Can be used to adsorb certain Removes what antibodies Plasma absorbed by this method should not be used for

Answer 25

 Can be used to adsorb certain antibodies.  Removes cold autoantibodies and anti-B and antibodies in the P blood group system (anti-P1).  Plasma adsorbed by this method should not be used for ABO typing.

Question 26

6. Rabbit erythrocyte stroma Decreases the strength of or complexity removes other ___ from plasma including _________ significant antibodies

Answer 26

 Decreases the strength of or complexly removes other IgM antibodies from plasma, including clinical significant antibodies.  Remains the adsorption medium of choice when an autoadsorption cannot be performed because a patient with a cold autoantibody has been recently transfused.  Available in commercial kits.

Question 27

Titration A technique used to measure the _______ of an antibody

Answer 27

Strength ( concentration)

Question 28

Serial dilution

Answer 28

2. Serial dilutions are made of the antibody containing plasma and tested against selected red blood cells to determine the highest dilution causing a positive reaction. The result or titer is expressed as the reciprocal of the highest plasma dilution reacting 1+.

Question 29

Titer scores

Answer 29

3. Titers can be resulted as a score, where a number is assigned to each positive reaction in the titration based on the strength of the reaction. 4. The sum of these scores reflects the total binding strength of the antigen and antibody molecules (known as titration score or avidity).

Question 30

7. Titration is most commonly used for determining

Answer 30

antibody activity and the potential severity of HDFN in alloimmunized pregnant women.

Question 31

8. Titration can be a useful aid in identifying antibodies to certain

Answer 31

high-incidence antigens.

Question 32

9. A titration can distinguish between a characteristic

Answer 32

high-titer, low-avidity antibody (HTLA) and a weakly reactive antibody with a low titer.

Question 33

2. If the autocontrol or DAT is negative and the patient has been transfused or pregnant, then the reactions are likely due to

Answer 33

alloantibodies. Both combinations of multiple antibodies and a single antibody to a high-incidence antigen may cause this pattern of reactivity.

Question 34

3. If the autocontrol or DAT is positive and the patient has not been transfused recently, then the results are likely due to an

Answer 34

autoantibody, either warm reactive, cold reactive, or both.

Question 35

4. If the autocontrol or DAT is positive and the patient has been transfused recently

Answer 35

the results may indicate either an autoantibody or a delayed serological transfusion reaction.

Question 36

False postives may result from

Answer 36

Pan agglutination or rouleaux

Question 37

Multiple antibodies 1. Certain combinations of antibodies may cause all or most cells tested to react

Answer 37

positively, making antibody exclusion and subsequent identification very difficult

Question 38

Multiple antibodies A combination of techniques is usually required to identify

Answer 38

identify the specificity of each antibody present within a complex mixture of them. The technique(s) that should be used depend(s) on which antibodies are suspected.

Question 39

C. Antibodies to High-Incidence Antigens

Answer 39

Negative autocontrol but almost all positive Screen cells, panel cells, donor RBCs reacting +

Question 40

Antibodies to High incidence antigens Testing with rare

Answer 40

Selected cells or plasma treated cells may confirm a + result Knowning the patients Ethnicity may help

Question 41

Warm autoantibodies

Answer 41

Warm autohemolytic anemia positive DAT, with screen, panel, and donor RBCs +

Question 42

3. An antibody that causes all cells tested to agglutinate is called a

Answer 42

Panagglutinatin

Question 43

Patients with warm autoantibodies tend to have a increase risk of

Answer 43

Alloimmunization compared to the general Population

Question 44

6. If the patient has not been transfused in the last 3 months, an ____________ can be performed and the adsorbed plasma tested for alloantibodies.

Answer 44

Autoabsorption

Question 45

Cold agglutinins

Answer 45

optimum reactivity between 37.7 and 77.0C cause problems with a DAT because they can interfere with the detection of more clinically significant antibodies, and interfere with ABO typing

Question 46

Cold autoantibodies most common types

Answer 46

specificities to I, i, IT, IH, and Pr antigens; autoanti-I is the most common.

Question 47

Identify using

Answer 47

Cord and Adult RBCs

Question 48

good indicators of clinical significance for cold-reactive autoantibodies.

Answer 48

antibody titers and thermal amplitude studies

Question 49

4. If cold autoantibodies may be masking alloantibodies, the autoantibodies can be removed from plasma by

Answer 49

autoadsorption using a low temperature or by adsorption with rabbit erythrocyte stroma.

Question 50

G. Cold Alloantibodies 1. Include specificities such as

Answer 50

anti-M, anti-N, anti-P1, anti-P, anti-Pk, anti-Lea, anti- Leb, and anti-Lua. they rarely cause in vivo hemolysis you can eliminate the IS, test with Anti-IgG, or eliminate microscopic readings

Question 51

Prewarm technique

Answer 51

is used to eliminate the effect of Cold reacting auto and allo antibodies but it has show to show a 47% reduction in the performance in these antibodies

Question 52

Cold agglutinins are shown to be a concern in cardiac bypass surgery because

Answer 52

the patient is constantly in a state of hypothermia Thermal amplitude and titer are a good indicator for potential complications

Question 53

If problems arise then the patient can be kept above

Answer 53

Body temperature or plasma exchange may be used to remove the cold autoantibody prior to surgery.

Question 54

2. With a delayed hemolytic reaction the patient exhibits symptoms of

Answer 54

Hemolysis but with serological transfusion reaction the patient does not exhibit symptoms of hemolysis

Question 55

The reaction pattern will mimic a high frequency antigen but the cross match with donor red cells will be negative

Answer 55

Antibiotic: gentamycin, neomycin, and chloramphenicol sugars: glucose dyes acriflavine and tartrazine Bacteriostatic/ antifungal reagents: paraben, thimerosal, sodium azide Chemical: citrate, inosine, EDTA

Question 56

HLA antigens reactions

Answer 56

Febrile, nonhemolytic reactions, and can cause platelet refractoriness. usually not clinically significant Plt transfusions may be given to absorb the HLA antigens off the RBC

Question 57

Antibodies to low incidence antigens

Answer 57

Specificities include Wra, Kpa, Jsa, Cw, Dia, Goa, SC2, Mia, Lua, Cob, and Ytb. Typical patterns of reactivity  The antibody screen is negative but one donor unit is incompatible if an IAT crossmatch is performed.

Question 58

Screen cells are

Answer 58

O in origin so A and B cells will not react

Question 59

6. Anti-Sda and anti-Lua are characteristic of a

Answer 59

Mixed field reaction

Question 60

5. Consent may be done at the time of admission or it may be obtained separately when the need to transfuse is identified.

Question 61

Transfusion request forms must be

Answer 61

Verbal or written and have the physician's name and phone number, the date and time, the phone number, and have the number and amount of test ordered

Question 62

– ABO typing may be performed at least

Answer 62

twice before transfusing RBCs

Question 63

When selecting components for ABO typing

Answer 63

The components may be ABO compatible or ABO identical