CST BLOG: Lab Expectations

The official blog of Cell Signaling Technology (CST), where we discuss what to expect from your time at the bench, share tips, tricks, and information.

Comparing Antibody Concentrations & Performance; CST Antibody Details You May Not Know

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When purchasing antibodies from Cell Signaling Technology (CST), you may notice that we typically recommend customers use our antibodies according to a specified dilution factor or dilution factor range, rather than at a specific concentration. This dilution factor range is based on real data generated in-house using our recommended protocols, reagents, and buffers to ensure optimal performance of the antibody, based on the activity within the respective application or assay.

What antibody concentration is optimal?

You may ask, doesn’t a higher concentration mean I am getting more antibody, and therefore a better value? Although many researchers believe that a higher antibody concentration leads to better results, the answer to this question is no. More antibody in your vial does not necessarily equate to a better value. Not all antibodies are equal in terms of performance, so this belief can mislead researchers into potentially choosing antibodies that may not perform optimally in their preferred application.

CST has an extensive portfolio of affinity-purified and Protein-A purified polyclonal antibodies and monoclonal antibodies. This means that the concentration of the antibody you are receiving is pure, high quality, and target-specific, rather than a mixture that may include non-specific antibodies and serum proteins. If you come across a CST primary antibody with a low concentration, it means the antibody is highly sensitive and has a high affinity for the target protein. To obtain optimal results, we recommend following the protocols found on the product web pages, as these are the same protocols used to generate the high-quality data seen on our website.

Some customers also ask, why does CST recommend a dilution factor range and not a specific concentration? Many researchers believe that by using a specific concentration of antibody, you will receive the same results and performance each time, no matter what clone or lot you purchase. However, since different antibodies have different levels of activity and sensitivity, and even purity, one cannot depend on using a specific antibody concentration alone. It is important to avoid treating every antibody, and antibody lot, the same way, as the concentrations and purity of an antibody can vary depending on the vendor.

Because CST recommends a specific dilution or dilution range, our antibodies are provided for a specific number of assays. This means that no matter the concentration, you will be able to perform the same number of experiments and observe consistent results from lot to lot. For example, most of our western blot-approved antibodies are recommended at a 1:1000 dilution, giving you 10 assays per 100ul.

No matter the concentration of a CST primary antibody, you can rest assured that you are using an antibody that is of high quality and performance and is backed by our Antibody Performance Guarantee. Should you have any questions about the use of CST products, remember that you can always reach out and talk to our experienced CST scientists by contacting Technical Support.


Alexandra Foley
Alexandra Foley
Alexandra is a scientific marketing writer at CST and the editor of the Lab Expectations blog.

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