A two-fold dilution reduces the concentration of a solution by a factor of two that is reduces the original concentration by one half. A series of two-fold dilutions is described as two-fold serial dilutions. In this manual, two-fold serial dilutions are carried out in small volumes in microwell plates. They are used in both the haemagglutination and haemagglutination inhibition tests to establish titres of the test samples.
A two-fold dilution
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Step 1. |
Use the micropipette to dispense 25 mL of PBS diluent to the first well. |
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Step 2. |
Use the micropipette to transfer 25 mL of the test solution to the first well. |
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Step 3. |
Use the micropipette to mix by drawing up the liquid and expelling it again. Carry out this action twice. |
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Step 4. |
The well now contains 25 mL of the original test solution diluted by one half in a total volume of 50 mL. |
Figure 24: A two-fold dilution
Two-fold serial dilutions
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Step 1. |
Use the micropipette to dispense 25 mL of the PBS diluent to all the wells across a row of a microwell plate. |
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Step 2. |
Use the micropipette to transfer 25 mL of the test solution to the first well and mix. This is the first two-fold dilution. |
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Step 3. |
Use the micropipette with the same tip to carry out a second two-fold dilution. |
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Step 4. |
Continue the series of two-fold dilutions until the second last well of the microwell plate. The last well is used as a control well in the haemagglutination and haemagglutination inhibition tests. |
Figure 25: Two-fold serial dilutions
