DIAGNOSING INFECTION Flashcards
Earlier, more accurate diagnosis leads to -
More effective treatment at earlier stage of disease progression.
ELISA -
Enzyme-linked immunosorbent assay.
What is ELISA?
Laboratory Technique.
Uses antibodies, enzymes etc as bio markers to detect particular molecules in body.
Test for small/large number of antigens/bio markers - screens for large number of conditions
ELISA Potential Method -
Patient’s body fluids added to wells on plate.
Range of antibodies added to wells.
Reaction between antibody - antigen - antigen - antibody complex formed.
Enzyme linked to antibody triggered to produce color change.
Molecules/antigens present identified.
ELISA used to detect -
Pathogens in body
Cancer cell markers
Cardiac Disease markers
Pregnancy
ELISA Advantage?
Early, rapid screening.
Wide range of diagnostic feedback from one test.
Pregnancy Testing
Egg implanted into Uterine Wall - increased levels of hCG (hormone chorionic gonadotropin) detected in blood/urine.
hCg antigens on surface of hormone detected by complementary antibodies immobilised on ELISA plate.
Antigen - antibody complex formed.
Linked enzyme produces color change.
Testing for Viral Pathogens
ELISA plate impregnated with viral antigens - coated with patient’s blood serum.
Patients blood contains complementary antibodies - evidence of infection.
Antigen - antibody complex formed,
Enzyme reaction = color change.
Enzyme attached to antigen - antibody complex - substrate added = color change.
How to measure degree of intensity of color?
Use colorimeter.
More intense a color - more antigens/antibodies in blood.
What stimulates the enzyme reaction?
Antigen - antibody complex stimulates the enzyme reaction - not substrate.
Substrate added as part of process.
Cytokines?
Chemicals released by T - Cells as part of immune response during infection.
Small proteins, help co-ordinate immune response
Found in blood, bio markers to identify TB, rheumatoid arthritis.
