ELISA Assay Service

Custom ELISA Kits Services

What is ELISA? Enzyme-linked immunosorbent assay (ELISA) is a biochemical technique used to detect the presence of a specific antigen or antibody in a sample. The ELISA has maintained its popularity for over 40 years due to its high specificity, sensitivity, and reliability – characteristics that customers consistently cite for using the method.

ELISA Services and Test Process

ELISA Assay Services

ELISA Services and Test Methods

Direct ELISA

The direct version of the ELISA assay uses monoclonal antibodies to test for a specific antigen. This form of ELISA testing is used primarily in the immunohistochemical staining of tissues and cells.


Direct ELISA, when compared to other forms of ELISA testing, is performed quickly because only one antibody is employed. This assay can be used to test specific antibody-to-antigen reactions, and helps avoid complications due to cross-reactivity between other antibodies. Disadvantages The primary antibody must be labeled individually, which can be time-consuming and arduous when performing multiple experiments. Also, the signal is not as amplified in direct ELISA, compared with the indirect approach, which can be a disadvantage in some applications involving trace analyte detection.

Indirect ELISA Test

The indirect detection method uses a labeled secondary antibody for detection and is the most popular format for ELISA. The secondary antibody has specificity for the primary antibody. In a sandwich ELISA, it is critical that the secondary antibody is specific for the detection of the primary antibody only (and not the capture antibody) or the assay will not be specific for the antigen. Generally, this is achieved by using capture and primary antibodies from different host species (e.g., mouse IgG and rabbit IgG, respectively). For sandwich assays, it is beneficial to use secondary antibodies that have been cross-adsorbed to remove any antibodies that have affinity for the capture antibody. 
The most powerful ELISA assay format is the sandwich assay. This type of capture assay is called a “sandwich” assay because the analyte to be measured is bound between two primary antibodies – the capture antibody and the detection antibody. The sandwich format is used because it is sensitive and robust.

Competitive ELISA Test

The competitive ELISA is used to quantify antigen using a competition method. Briefly, the free antigen and antibody are incubated to form antigen-antibody complex and then the complex is added to an antigen-coated surface in the assay plate. The unbound antibody-antigen complex is washed off before adding enzyme-linked secondary antibody against the primary antibody. The substrate is then added and the antigen concentration is subsequently determined by the signal strength elicited by the enzyme-substrate reaction. In this assay, the enzyme-linked secondary antibody competes with the sample antigen, which is associated with the primary antibody.

Our Service

With a professional ELISA team and state-of-the-art equipment, KareBay Biochem will provide you with the highest quality service. It is simple to work with us. You send us your samples, we send you back the test results.

How to get started

Please contact us with your ELISA Services requests at service@karebaybio.com and we will reply with a detailed quote as soon as possible. This process usually takes between 24 and 48 hours and the quote will include an estimated price as well as the time required to complete the project. All inquiries and subsequent projects are handled in strict confidence and will be backed by a confidentiality agreement if desired.