Urine and diagnosis

What do pregnancy tests detect?

Hormone human chorionic gonadotropin (hcG) - only found in pregnant woman

Monoclonal antibodies

Antibodies from a single clone of cells that are produced to target particular cells or chemicals in the body

Making monoclonal antibodies

1. Mouse injected w. hcG, so it makes its antibody

2. B-cells that make required antibody are removed from spleen of mouse and fused w. myeloma

   1. Type of cancer cell that divides v. rapidly 

3. Fused cell = hybridoma 

4. Reproduced rapidly, so many B-cells making desired antibody

5. Antibodies collected, purified and used 

Stages in pregnancy test

1. Wick soaked in 1st urine passed in morning (highest hcG)

2. When urine applied to application area, hcG will bind to mobile monoclonal antibodies on beads 

3. Forms hcG-antibody complex

   1. Form coloured line if woman is pregnant

4. Urine moves up strip, carrying beads w. it

5. Reaches a window w. immobilised monoclonal antibodies

   1. Binds to any mobile antibodies (control)

6. Pregnant = 2 lines

Anabolic steroids

Drugs that mimic the action of testosterone and stimulate the growth of muscles 

Testing for anabolic steroids

As they are excreted in urine:

• Tested for in urine using gas chromatography & mass spec

  • Urine vaporised w. known solvent & passed along tube

  • Lining of tube absorbs gases & analysed to give chromatogram that is read to show drugs present 

Testing for drugs

1. 1st sample may be tested by immunoassay, using monoclonal antibodies to bind to drug/breakdown prod.

2. If positive, run thru gas chroma / mass spec to confirm its presence