Laboratory Activity 5 – Antibody Titration

Question 1

the process of diluting the patient’s serum by either of the two methods, namely serial dilution or fixed dilution.

Answer 1

Antibody titration

Question 2

The patient’s serum is added with a definite amount of .

Answer 2

diluent

Question 3

As dilution progresses, the amount of the [?] decreases.

Answer 3

antibody

Question 4

When a definite amount of [?] is added, the antibody in the different dilutions reacts to give different grades/strength of the reaction.

Answer 4

antigen

Question 5

The highest dilution that gives the expected result (e.g., agglutination) is considered the

Answer 5

titer of the antibody.

Question 6

[?] for a particular disease may be of diagnostic value.

Answer 6

Antibody titer

Question 6

[?] for a particular disease may be of diagnostic value.

Answer 6

Antibody titer

Question 7

When it is exceedingly high, a [?] may be considered significant.

Answer 7

single titer

Question 8

diagnosis is based on the [?] between paired serum samples obtained at an interval.

Answer 8

fourfold increase in antibody titer

Question 9

is a semiquantitative method used to determine the concentration of antibodies in a serum sample or to compare the strength of antigen expression on different red cell samples.

Answer 9

Antibody titration

Question 10

This involves the process of diluting the patient’s serum by either serial or fixed dilution.

Answer 10

Antibody titration

Question 11

[?], the solute, is made weaker by adding diluent so that the antibody present is not as concentrated.

Answer 11

Patient serum

Question 12

As dilution progresses, the amount of the [?] decreases.

Answer 12

antibody

Question 13

When a definite amount of antigen is added, the [?] in the different dilutions reacts to give different grades/strength of the reaction.

Answer 13

antibody

Question 14

The highest dilution (end-point) that gives the expected result (for example, agglutination or hemolysis) is considered as the

Answer 14

antibody titer

Question 14

A dilution involves two entities:
- the [?], which is the patient’s serum
- the [?[, which is the medium making up the rest of the solution, usually normal saline solution (NSS)

Answer 14

solute
diluent

Question 15

The relationship between these solute and the diluent is expressed as a [?].

Answer 15

fraction

Question 16

For example, a 1:20 dilution implies 1 part of the patient’s serum and 19 parts of diluent. The number on the bottom of the fraction is the [?], reached by adding the volumes of the solute and diluent

Answer 16

total volume

Question 17

The number on the bottom of the fraction is the [?], reached by adding the volumes of the solute and diluent together.

Answer 17

total volume

Question 18

To find the total volume, the amount of solute, or the amount of diluent needed to make a dilution, in a single dilution the following formula may be used:

Question 19

This is an example of a [?] – dilution series in which all dilutions, including or following the first one, are the same.

Answer 19

serial dilution

Question 20

If you are to perform the given serial dilution protocol, refer to the image above.
a. Place [?] of diluent in each tube.
b. Place [?] of serum to the Control Tube and Tube 1. Mix the contents. Each tube will yield a 1:2 dilution.
c. Transfer [?] of the serum-diluent mixture from the Tube 1 to Tube 2. Mix the contents. Tube 2 will yield a 1:4 dilution.
d. Transfer [?] of the serum-diluent mixture from the Tube 2 to Tube 3. Mix the contents. Tube 3 will yield a 1:8 dilution.
e. Do the same to the succeeding tubes, where [?] of serum-diluent mixture is transferred from the previous tube to the next tube. For the last tube, discard [?] so that the volumes in all tubes are equal (i.e., 0.1 mL).

Answer 20

0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL

Question 21

The calculation of dilution for each tube was computed using the following formula given in your laboratory manual.

Question 22

0.1 mL (the amount of diluent initially placed in the tube)

Answer 22

• Original Volume

Question 23

0.1 mL + 0.1 mL (Original volume + Volume added to the tube)

Answer 23

• Total Volume

Question 24

1 (use 1 if the preceding tube is the undiluted serum sample)

Answer 24

• Original dilution

Question 25

x, unknown

Answer 25

• Resulting dilution

Question 26

A central concept of serologic testing is the manifestation of a [?], of an antibody.

Answer 26

rise in titer, or concentration

Question 27

is defined as the reciprocal of the highest dilution of the patient’s serum in which the antibody is still detectable

Answer 27

antibody titer

Question 28

is read at the highest dilution of serum that gives a positive reaction with the antigen

Answer 28

titer

Question 29

If a serum sample has been diluted [?] and reacts positively with the antigen suspension used in the testing process, and if the next highest dilution of [?] does not give a positive reaction, the titer is read at [?].

Answer 29

1:64
1:128
64

Question 30

A high titer indicates that there is a relatively [?] present in the serum.

Answer 30

high concentration of the antibody

Question 31

an indication of a current infection

Answer 31

• increase in the patient’s titer of two doubling dilutions
• ## a positive result of 1:8 to a positive result of 1:32 over several weeks

Question 32

This is known as a fourfold rise in the antibody titer.

Answer 32

• increase in the patient’s titer of two doubling dilutions
• a positive result of 1:8 to a positive result of 1:32 over several weeks