2.11 Pregnancy Test

Question 1

What is the pregnancy hormone?

Answer 1

Human chorionic gonadotrophin (hCG)

Question 2

Describe the components of the testing strip of a pregnancy test (2)

Answer 2

• On the right side, there are a lot of monoclonal antibodies which are specific to HCG which means that they can bind to the HCG hormone if they come into contact with it. These antibodies are fixed to the test strip.
• On the left side, it is the part where the woman urinates on. There are blue beads which are covered in the same monoclonal antibodies as on the right sight. However, they are not fixed so can spread throughout the strip.

Question 3

Describe how a pregnancy test works with someone who isn’t pregnant

Answer 3

The urine will wash the unfixed beads along the test strip, and they float right over the fixed antibodies. So, the test strip will not go blue.

Question 4

Describe how a pregnancy test works with someone who is pregnant

Answer 4

If you are pregnant your urine will contain HCG. So as the urine hits the left side of the strip, the HCG will bind to the antibodies on the blue beads. So now, as the blue beads flow over the test strip, the HCG that they are carrying binds to the fixed antibodies and the beads get stuck to them. By trapping loads of these tiny blue beads, the entire line becomes blue.

Question 5

Which type of antibodies does the pregnancy test use?

Answer 5

Monoclonal antibodies

Question 6

What are the benefits of the pregnancy test? (2)

Answer 6

• Cheap
• Quick