how does your new blood test work?

Question: how does your new blood test work?
- Keywords:
  blood,
  cancer,
  how,
  how does,
  test,
  work
Asked by kbcars1 to Sarah on 24 Mar 2011.
- Sarah Thomas answered on 24 Mar 2011:
  
  well the doctor would take a small sample of the patients blood and then add my dye to it. The dye binds to cancer chemicals that leak out of tumours into the blood stream. When it binds it becomes fluorescent, so if the sample glows, it is a positive result for cancer.
  
  The fluorescence is very sentitive so it should be able to detect very low concentrations of cancer chemicals in the blood. This means that the test should be able to detect all different types of cancer and cancer in its early stages.

Question: how does your new blood test work?