Eliza test

• What does the Elisa test quantify?

  The level of a protein
• What does Elisa stand for?

  Enzyme-linked immunosorbent assay
• Why do we need to determine the quantity of a protein?

  To determine the level of an antigen in blood
• What are the stages of the Elisa test?

  1. Apply sample containing antigen to well
  2. Wash to remove unbound antigens
  3. Add specific antibody to bind antigen
  4. Wash to remove excess antibodies
  5. Add second antibody with enzyme
  6. Wash to remove unbound second antibody
  7. Add substrate for enzyme
  8. Measure color intensity to quantify antigen
• What type of plates are often used for Elisa tests?

  Plastic plates with small wells
• What happens to the antigen molecules when the sample is applied to the well?

  They stick to the material at the bottom
• Why do we wash the well after applying the sample?

  To remove unbound antigen molecules
• What is the role of the first antibody in the Elisa test?

  It specifically binds to the antigen
• What does the second antibody do in the Elisa test?

  It binds to the first antibody and has an enzyme
• Why do we wash the well after adding the second antibody?

  To remove unbound second antibody
• What happens when the substrate is added to the well?

  The enzyme converts it into a colored product
• How is the intensity of the color related to the antigen level?

  It depends on the number of antigen molecules
• Why do we use different dilutions of the sample in Elisa tests?

  To ensure all antigen molecules stick
• What problem does using a range of dilutions solve?

  It prevents overloading the well with antigen
• How are Elisa tests often automated?

  To read a large number of samples accurately
• For what purpose is Elisa a valuable method?

  Testing for infectious diseases like HIV
• What is the significance of the color intensity in an Elisa test?

  • Indicates the amount of antigen present
  • Higher intensity means more antigen
  • Used for quantitative analysis