The enzyme–linked immunosorbent assay (ELISA) is a micro-plate-based detection technique. It uses antibodies and enzymes to identify substances in liquid samples, such as plasma or tissue lysate. With its effectiveness and convenience, it has wide applications in biomedical research, diagnosing diseases, and the food industry to detect harmful substances like allergens.
Selecting the appropriate ELISA kit may be challenging since there are varieties in the market, and they’re only sometimes created equally. But before you choose an ELISA kit, here are some factors to consider:
1. Type Of ELISA
Before choosing an ELISA kit, you must understand the different types used to detect enzymes and antibodies. Each technique may require another kit; therefore, you need a suitable kit for a comprehensive analysis and results.
Here are the common ELISA methods:
- Indirect ELISA: It detects an antibody in a sample through a second conjugated antibody.
- Sandwich ELISA: Aids in detecting the presence of the antigen in a sample. It’s a common ELISA type because it has superior sensitivity and specificity. But its accuracy depends on the use of a matched pair of antibodies.
- Competitive ELISA: It’s considered the most challenging ELISA format to develop since it is used to detect the concentration of an antigen in a sample with a single epitope.
- Direct ELISA: It differs from other ELISA methods because the antigen is directly bound to the well of a microplate, and the antibody binding gets to be directly conjugated.
Before you sift through numerous choices on sites like https://shop.surmodics.com/elisa-assay and similar others for ELISA kits, research what kit would suit the test you want to do.
2. The Type Of Analyte Detected
It’s appropriate to identify the type of analyte you want to detect. In most instances, a sandwich type of ELISA kit is considered for detecting large proteins with large epitomes, for instance, cytokine. Most commercially available ELISA kits have been validated based on serum and supernates. Therefore, it’s essential to carefully read the product instructions and descriptions to ensure the kit you purchase is suitable for the sample that will be analyzed.
3. Detection System
There are varieties of detection systems available in ELISA. The commonly available systems are the luminescent, fluorescent, and colorimetric methods. All ELISA entails immobilizing the analyte to a surface and using an enzyme label and the matching substrate. Considering the most appropriate detection system helps you achieve good results.
4. Antibody Types
To make it easier for you while selecting the kit, consider contacting the ELISA kit suppliers so they can give you details concerning the type of antibodies used in the kit. That will be significant in helping you to know if it’s a polyclonal or monoclonal type of antibody.
In most instances, the sandwich type of kit is appropriate for the polyclonal antibody, mainly for capturing the antibody. In contrast, the monoclonal antibody is purposely used to detect the antibody.
5. Species Tested
The most common ELISA kits are used for mice, humans, and rats samples. But if it’s from unique models such as canines and monkeys, a limited number of ELISA kits will be available. Therefore, you’ll need to pick a kit that’s considered valid for the species with homology with your exact sample species.
While selecting the kit, ensuring the manufacturer has validated your sample type is crucial. In most instances, the ELISA kits have been validated for numerous ranges of samples like a serum, cell, cell culture supernates, plasma tissue, and cell lysate. When diagnosing a disease, you should know all the details, including the steps and procedures of the test. Thus, consider selecting one that will be compatible with the samples.
6. Sensitivity Of The Kit
Get to know the concentration of the target analyte in the sample. If you have no idea, consider an ELISA kit with a wide detection range. If you know that your samples have shallow levels of the target analyte, then you have to select ELISA kits with a high sensitivity level of detection.
Knowing the sensitivity and assay range before considering buying any ELISA kit is appropriate. Always be aware that the more sensitive the kit is, the lower the operating range.
7. Reason For The Analysis
ELISA can be used for the analysis of quantitative and qualitative results. Qualitative can determine simple negative or positive results of a given sample, while quantitative ELISA can determine the concentration of the given analyte through a standard curve. It, therefore, depends on you if you want to detect the presence of an analyte or quantify it. Based on the purpose of the analyte, you should select a suitable ELISA kit.
Conclusion
Selecting an ELISA kit can be challenging and confusing, especially if it’s your first use. Therefore, it’s essential to consider factors like the detection system, types of species studies, reason for the analysis, sensitivity of the kit, and the type of analyte being detected to choose an appropriate ELISA kit for accurate and successful results.