Immunoassays

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Immunoassays

• Diane C. Jette, Ph.D.
• BioMedica Diagnostics Inc.

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Test Menu

• Infectious Diseases
• Cardiac Markers
• Cancer Screening
• Fertility / Hormones
• Drugs of Abuse

• Other Tests
• IgE
• Rh Factor
• Occult Blood
• TSH, T3, T4
• Blood Grouping

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Test Formats Available

• Latex Agglutination
• DIPSTICK
• Card Format
• Cartridge Format
• ELISA Format with Plate Reader

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Structure of IgG
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Structure of IgM
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Sandwich ELISA Procedure

• Antibody coated on plate.
• Incubate with sample containing antigen.
• Wash away unbound material.
• Incubate with antibody-enzyme conjugate.
• Wash away unbound conjugate.
• Add substrate.
• Enzyme acts on substrate and produces color
  change.
• Measure amount of color produced.
• Amount of antigen present is proportional to the
  amount of color produced.

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ELISA Sandwich Format
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Sandwich Assay Results
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ELISA Inhibition Assay Procedure

• Antigen coated on plate.
• Incubate with sample containing antigen and
  enzyme-antibody conjugate.
• Antigen in solution binds to enzyme-antibody
  conjugate preventing binding to antigen on plate.
• Wash away all unbound material.
• Add substrate.
• Enzyme acts on substrate to produce a color
  change.
• Measure the amount of color.
• The amount of antigen present is inversely
  proportional to the amount of color produced.

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ELISA Inhibition Format
A
A
A
A
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Inhibition Assay Results
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Agglutination Assay Procedure

• Antibody Detection
• Antigen coated on latex particles.
• Incubate with sample containing antibody.
• Antibody binding to antigen causes cross-linking
  of latex beads.
• Agglutination is observed.

• Antigen Detection
• Antibody coated on latex particles.
• Incubate with sample containing antigen.
• Antigen binding to antibody causes cross-linking
  of latex beads.
• Agglutination is observed.

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Latex Agglutination Assay
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Latex Agglutination
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DIPSTICK Format
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CARD Format
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Cartridge Format