Sandwich ELISA Protocol

Figure 1: A schematic of a Sandwich ELISA, whereby the capture antibody and detection antibody have bound to the protein of interest.

What is a sandwich ELISA?

Sandwich ELISA (Enzyme-Linked ImmunoSorbent Assay) is a antibody based technique that allows researchers to quantify the amount of protein, hormone or analyte of interest in a sample. Capture and detection antibodies bind to non-overlapping epitopes on the protein to sandwich the protein, hence the name, Sandwich ELISA. Following the addition of the detection antibody, a chemical substrate is added (such as TMB) to produce a colorimetric signal that can be read by an ELISA plate reader.  

Sandwich ELISA antibodies

Antibodies used to create a Sandwich ELISA can be either polyclonal or monoclonal antibodies depending on the specificity, sensitivity and analyte being detected.

> Polyclonal antibodies

Polyclonal antibodies are often used to pull down as much analyte as possible in a sample. Polyclonal antibodies can bind to multiple facets of an epitope therefore, provide an increased capture opportunity for detecting proteins of interest.

> Monoclonal antibodies

Monoclonal antibodies allow researchers to pull down a single antigen. Therefore, allow researchers to distinguish between subtle differences in proteins. Monoclonal antibodies also provide increased consistency in data versus polyclonal antibodies.

Advantages of a Sandwich ELISA

Advantage Description

No sample purification required

Sandwich ELISA assays allow for the measure of proteins/analytes in complex samples without the need for purification.

High specificity

Since capture and detection antibodies are used, a Sandwich ELISA assay has increased sensitivity versus a direct or indirect ELISA assay.


Versus other EIA methods such as a Western Blot, the Sandwich ELISA assay allows researchers to quantify the amount of protein in a sample.

Sandwich ELISA Kits

PharmaGenie Sandwich ELISA Kits

PharmaGenie ELISA Kits from ELISA Genie are high quality ELISA Kits designed to meet the needs of pharma and biotech research. Focussing on high quality monoclonal antibody pairs & reagents that have been been validated according ISO 9001:2000 quality systems, PharmaGenie ELISA Kits are excellent assays to help discover our future.

Human IL-2 PharmaGenie ELISA Kit