Laboratory Activity 5 – Antibody Titration Flashcards
the process of diluting the patient’s serum by either of the two methods, namely serial dilution or fixed dilution.
Antibody titration
The patient’s serum is added with a definite amount of .
diluent
As dilution progresses, the amount of the [?] decreases.
antibody
When a definite amount of [?] is added, the antibody in the different dilutions reacts to give different grades/strength of the reaction.
antigen
The highest dilution that gives the expected result (e.g., agglutination) is considered the
titer of the antibody.
[?] for a particular disease may be of diagnostic value.
Antibody titer
[?] for a particular disease may be of diagnostic value.
Antibody titer
When it is exceedingly high, a [?] may be considered significant.
single titer
diagnosis is based on the [?] between paired serum samples obtained at an interval.
fourfold increase in antibody titer
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.
Antibody titration
This involves the process of diluting the patient’s serum by either serial or fixed dilution.
Antibody titration
[?], the solute, is made weaker by adding diluent so that the antibody present is not as concentrated.
Patient serum
As dilution progresses, the amount of the [?] decreases.
antibody
When a definite amount of antigen is added, the [?] in the different dilutions reacts to give different grades/strength of the reaction.
antibody
The highest dilution (end-point) that gives the expected result (for example, agglutination or hemolysis) is considered as the
antibody titer
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)
solute
diluent
The relationship between these solute and the diluent is expressed as a [?].
fraction
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
total volume
The number on the bottom of the fraction is the [?], reached by adding the volumes of the solute and diluent together.
total volume
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:
This is an example of a [?] – dilution series in which all dilutions, including or following the first one, are the same.
serial dilution
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).
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
0.1 mL
The calculation of dilution for each tube was computed using the following formula given in your laboratory manual.
0.1 mL (the amount of diluent initially placed in the tube)
• Original Volume
0.1 mL + 0.1 mL (Original volume + Volume added to the tube)
• Total Volume
1 (use 1 if the preceding tube is the undiluted serum sample)
• Original dilution
x, unknown
• Resulting dilution
A central concept of serologic testing is the manifestation of a [?], of an antibody.
rise in titer, or concentration
is defined as the reciprocal of the highest dilution of the patient’s serum in which the antibody is still detectable
antibody titer
is read at the highest dilution of serum that gives a positive reaction with the antigen
titer
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 [?].
1:64
1:128
64
A high titer indicates that there is a relatively [?] present in the serum.
high concentration of the antibody
an indication of a current infection
- 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
This is known as a fourfold rise in the antibody titer.
- 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
