Question

In a typical ELISA, lab technicians use separate wells for positive controls, negative controls, and patient samples. You modeled the well of a positive patient sample.

a) Use your shapes to model a positive control. Describe the necessary components and steps.
b) Use your shapes to model a negative patient sample. Describe the necessary components and steps.

Answer 1

A positive control in ELISA requires adding known antigen to the wells after primary antibody application and blocking, followed by the enzyme-linked secondary antibody and substrate to produce a color. A negative patient sample will not produce color after the same procedure if the specific antigen is not present.

Step-by-step explanation:

To model a positive control in a typical ELISA, start by coating the wells with a primary antibody that will capture the antigen of interest. After incubation, wash the well to remove unbound antibodies. Block any nonspecific binding sites with a protein such as casein. Add a known quantity of antigen to create a standard curve, followed by a secondary antibody conjugated to an enzyme. Upon adding a chromogenic substrate, the enzyme will catalyze the reaction and produce a colored product, indicating a positive result.

To model a negative patient sample in ELISA, follow the same steps of adding primary antibody, washing, and blocking. Instead of adding antigen, add the patient sample. If the antigen of interest is absent, the primary antibody will not capture anything, and subsequent washes will remove any unbound antibodies. After adding the secondary antibody and substrate, the lack of color change would indicate a negative result.