We can also set up the Enzyme-Linked Immunosorbent Assay (ELISA) or aka Enzyme Immunoassay (EIA) to tell us relative amounts of a ligand/antigen/epitope/pathogen that we want to assess.
If this is the scenario we want, we have to first place different known amounts of the ligand/antigen/epitope/pathogen on a microtitre plate in decreasing amounts, to act as what we call a standard curve. Standard curves may also be called calibration curves.
Based on the reading of the known amounts, we can infer the amount of ligand/antigen/epitope/pathogen in the assay.
For some pathogens, amounts are important so we may want to know not just whether it's there, but how much of the ligand/antigen/epitope/pathogen is there.
For simple yes/no answers in ELISAs, a cut-off value is calculated based on the reading of the negative control. A ratio of the absorbance readings and the cut-off value is used to determine whether an interaction exists between the ligand/antigen/epitope/pathogen and the antibody that is used in the enzyme immunoassay.
For quantitative ELISAs where the relative amounts of the ligand/antigen/epitope/pathogen/protein/hormone/cytokine is to me measured, a plot of the absorbance on the y-axis versus the the known ligand/antigen/epitope/pathogen/protein/hormone/cytokine used for the standard curve is created.
A linear curve fit or a sigmoidal curve may then be used depending on the scattering of the data points.
Most commonly, a 4 parameter logistic (4PL) analysis is used to determine the unknown concentrations.
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This video is about Enzyme linked immunosorbernt assay, enzyme immunoassay, ELISA, immunoassay, linear curve fit, sigmoidal curves, dose response curves, 4 parameter logistic analysis, qualitative elisa data, quantitative elisa data, qualitative versus quantitative elisa data, cut off value in elisa, elisa cut off value, cut-off value elisa, elisa, absorbance ratio, optical density, elisa optical density, equation of a line, line of best fit, elisa data, maximum signal, minimum signal, inflection point, concentration, half maximal signal, L50, and enzyme-linked immunosorbent assay.
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//MUSIC
Music: Shine by Joakim Karud
joakimkarud.com/use-my-music/
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// ADWOA
I'm Adwoa (Adwoa Biotech), a Biotechnology graduate. I’ve worked in medical research for years and want to be useful to people new to the lab life. This channel takes you through some of the techniques and concepts I've learnt working as a Research Assistant. Hopefully it helps if you're new to the topic/technique.
7 апр 2021
