Yes and no. Antibody manufacturers use different protocols to validate or verify their antibodies. Some are very careful in this process while others are obscure. In both cases, you will find validation details on the product data-sheet. Standard validation methods include flow cytometry, Western blot, immunohistochemistry, CRO Assay Services and ELISA.
At least one of these should be done by the manufacturer and described in detail in the datasheet. If in doubt, you can always contact your provider to inquire about the further application and sample types. There may be other, unpublished data that can help you.
Validation takes a long time due to every parameter like sample type, conditions eg. Temperature, pH, changes in nature, incubation time and administration should be assessed on an individual basis. So never assume that antibodies that have been confirmed in some applications will work in other similar applications. Let's look at the various ways in which antibodies can be validated either by the manufacturer or by the end-user.
Most manufacturers have shown that their antibodies "work" by Western blotting of whole-cell lysates. However, if this is the only available verification record, you should proceed with caution.
The western dots can reveal bands of expected molecular weight, but they don't tell you anything about the identities of the proteins found, nor do they rule out the possibility that antibodies have an affinity for more than one protein in the same size range.
Another disadvantage is that you can see additional bands of different sizes, but with the Western blot alone you cannot tell if the protein is a non-target protein or your target conformation with post-translational modification.