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Frequently Asked Questions

Here are answers to the most frequently asked questions

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A: In line with Cell Signaling Technology’s (CST) environmentally conscientious efforts, we have been shipping antibodies at room temperature since 2003 when possible to reduce packing materials waste. Each CST™ antibody is stability tested by exposure to room temperature and 37°C for one week followed by western blot testing to ensure no change in antibody performance. If you received an antibody at room temperature, rest assured that it has passed stability testing and that the antibody performance is still optimal. Upon receipt, please store the antibody as indicated on the product datasheet.
A: Please store the antibodies in the original tube at -20°C and do not aliquot as this may introduce variables and waste antibody. The antibodies are provided in a buffer that contains 50% glycerol and do not freeze under the recommended storage conditions. This prevents degradation of the antibody due to repeated freeze-thaw cycles. Conjugated antibodies may indicate storage at 4°C, please store as suggested on the product datasheet.
A: Possibly. CST scientists test all CST antibodies on multiple species, if possible (this depends on the target and the experimental systems available). If tested species do not cross-react, we do not list that species as cross-reactive. However, it is possible that the model we test may contain a low level of particular protein or the inductions we used are not ideal in that particular model system. If you need additional information regarding cross-reactivity with a particular species, please feel free to contact CST technical support team at [email protected] for assistance.
A: CST™ antibodies are optimized to provide the strongest signal with the least background, using our standard western blotting protocol. Using the recommended, optimized CST protocol saves you costly time and materials.
A: CST routinely tests antibodies in relevant applications. Those that pass rigorous application-specific validation standards are recommended. We only recommend applications that have passed rigorous validation standards, if performance data is ambiguous we do not recommend the application. Please contact the CST technical support team at [email protected] for more information about a particular antibody, or for a recommendation on which antibody will perform best in your desired application.
A: CST does not routinely test antibodies for fluoresecent western blotting, though many work well in this application. Performing a fluorescent western blot using CST™ antibodies requires a modified immunoblotting protocol. We find that omitting Tween® 20 detergent from the blocking step (using only 5% nonfat dry milk in TBS) and drying the membrane prior to imaging are the only necessary changes from our standard protocol. Full details can be found in our Fluorescent Western Immunoblotting Protocol (Primary Ab Incubation In BSA) and our Fluorescent Western Immunoblotting Protocol (Primary Ab Incubation In Milk). Additionally, our Prestained Protein Marker, Broad Range (Premixed Format) #7720 serves well as a marker in fluorescent western blotting because it is autofluorescent at near-infrared wavelengths.
A: Often, CST offers more than one antibody against a target. To chose the antibody that will perform the best in your desired application, please contact CST technical support at [email protected] for assistance in selecting the optimal antibody for your application.
A: CST scientists test all our products in relevant applications such as western blotting, immunoprecipitation, immunofluorescence, immunohistochemistry, flow cytometry, and chromatin immunoprecipitation. When an antibody is recommend for a particular application, it indicates that the antibody has passed rigorous application-specific testing standards. Additionally, our scientists create specialized (optimized) immunostaining protocols for individual products, saving you time and reagents. We routinely test our antibodies on multiple species including human, monkey, mouse, and rat. The high quality of our products is the most important consideration at CST. If you are interested in a particular application not listed on the product webpage, please contact CST technical support at [email protected] for further information.
A: CST scientists strive to achieve product consistency from lot to lot. As a standard, we routinely test the new lot side-by-side with the old lot in multiple assays, to ensure equivalent activity. The recommended dilution ranges for each application are optimized for each product following our protocols.
A: At CST, we formulate antibodies based on activity to eliminate the necessity for you to make adjustments. Concentrations between lots of antibodies are sometimes adjusted to optimize results. If you are looking for the concentration of a recently purchased antibody, Certificates of Analysis for the current shipping lot of many of our products are now available on the product webpage or at For the concentration of a previous antibody lot, please contact CST technical support at [email protected].

A: When stored under the recommended conditions, CST products can be expected to perform at optimal levels during the specified shelf-life period.

The product you receive will have one of two dates listed on its packaging. If the date is preceded by “Ref:”, then it is a “Reference Date”. This date indicates the date (month and year) that the product was filled or packaged. For single component products such as individual antibodies, the starting point for the expected shelf-life is indicated by the reference date printed on the vial label. For multi-component kit products the reference date printed on the barcoded kit box label indicates the starting point for the expected shelf-life.

If the date is preceded by “Best:”, then it is a “Best By” date. This date indicates the end point of the shelf life of the product. Please expect the product to perform at optimal levels until this date, as long as it is stored under the recommended conditions. Click here for a listing of shelf-life information by product type.

A: For custom (carrier-free) orders, many antibodies prepared formulated in PBS without BSA or glycerol are in stock. This formulation is amenable to conjugation and can be conjugated to fluorophores, beads, or dyes. In order to meet the requirements of your assay or your laboratory, we are also happy to provide you with bulk sales. Please contact us for pricing and availability at [email protected].
A: CST does not develop custom antibodies, but we are happy to accept your target suggestions. Please submit your suggestions here or email us at [email protected] and a CST scientist will contact you shortly.

A: For general product questions, contact [email protected].

For specific technical questions, contact [email protected].

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