This document discusses the prozone phenomenon, serial dilution, titer, and titration. The prozone phenomenon occurs when there is too much antibody present, blocking the reaction. Serial dilution is used to solve this by diluting the sample until the reaction occurs. Titer refers to the reciprocal of the last dilution tube that shows a positive reaction, and is a measure of antibody concentration or antigen expression level. Titration is a semi-quantitative method used to determine these values through serial dilution and observing the reaction.

1. Prozone phenomenon
Serial dilution
Titer
Ayed Hatem
BCs/KKU

2. • Prozone phenomena
• In an agglutination or precipitation reaction,
the zone of relatively high antibody
concentrations within which no reaction
occurs. As the antibody concentration is
lowered below the prozone, the reaction
occurs.(solve by dilution)
• This phenomenon may be due simply to
antibody excess or it may be due to blocking
antibody or to nonspecific inhibitors in serum.

3. Precipitation Curve

5. An example of prozone
phenomenon.
* Sample 2 is an example of the prozone phenomenon

6. Serial dilution

7. Serial Dilution

9. We then transfer 1 ml of the original solution into the tube with
9ml of water.
Now, We have 1 ml (sample) + 9 ml (Water)=10

13. What is the concentration in
tube #3?

14. To Find The Concentration in
Tube # 3

15. Cont..

16. Continue

18. Constant Formula

19. Titer

20. Titration
• is a semi-quantitative method used to
determine the concentration of antibody in
a serum sample or to compare the
strength of antigen expression on different
samples.
• Speed and strength of agglutination is
termed as avidity.

21. Titers
• TITERS are reported out as the reciprocal
of the last tube giving a positive reaction.
• So if tube 2 was the endpoint, the dilution
is 1:800 the titer is reported out as
800/1= 800.

22. The end..