How to use the test. For a printable version of these notes see the menu bar at the left.

1. Simulate the spread of infection by sharing 'serum' samples with other members of the class.
2. Carry out the test to find out who is infected (ie positive for the disease antigen).
3. Use the information to find out who was the original source of the infection

1. Simulate the spread of infection

• Label your serum sample with your initials.
• Use a small pipette to add your serum sample to your partner’s and mix them together. (It is a good idea to label the small pipette also with your initials.)
• Return half of the mixed sample to your sample tube.
• After each exchange make a note of who you have exchanged serum with.
• Repeat this step with a different person. You and your original partner should not exchange samples with the two members of the same partnership.
• If there are more than 8 people in the class you should do a third round of exchanges.
• If there are more than 16 in the class you can do a fourth round.