Which of the following best defines an ELISA and the functional role of an enzyme linked to an antibody in the assay?

You are given a blank 96-well plate and asked to run a sandwich ELISA. Which sequence below correctly orders the five general steps and gives the primary purpose of the blocking step?

Which workflow correctly describes the five main steps of an indirect ELISA and the rationale for how the assay demonstrates prior exposure to an antigen?

A standard curve is prepared with standards: 0, 10, 20, 40, 80 ng/mL giving absorbances of 0.05, 0.15, 0.25, 0.45, 0.85 respectively. An unknown sample wells reads 0.33 absorbance. Using a linear fit, estimate the concentration of the unknown sample in ng/mL.

You are designing a sandwich ELISA to detect Borrelia burgdorferi OspC antigen in patient serum. Which design choice below is most appropriate for capture/detection reagents and plate controls to ensure reliable diagnosis across multiple samples?