why is it necessary to have a serial dilution in an ELISA?

Hi Jenn,

Serial dilution allows for quantitative analysis of the ELISA; let me explain.  In quantitative ELISA, the optical density (OD) of the sample is compared to a standard curve, which is typically a serial dilution of a known-concentration solution of the target molecule.  So just imagine yo get your results from your test sample and you get an OD of 1, then you must look at your standard curve that gave approximately 1 and it tells you the concentration of your sample.  So lets say I want to find the amount of a certain protein in blood (lets say pregnancy test so we are looking for hCG better known as Human Chorionic Gonadotropin) well we get our sample of blood we do the dilution and run the ELISA getting an OD.  We refer back to our standard OD curve and find out that the patient has a certain concentration of hCG.

Hopefully that answered your question, have a good weekend.