There are many ways to test for mold. Mold sampling methods include taking a sample of mold with tape, with a vacuum suction method, or by swabbing the surface where the mold is. Some mold collection methods are better for mold sampling than others. It is good to be aware of the limitations of each method before deciding which to use.
Some mold sampling kits necessitate the cultivation of mold for identification. The user would put the mold on a culture and allow the mold to grow in order to determine the type of mold that it is. The problem with conducting mold sampling without professional advice is that it may be unclear which is the best area to sample (there may be harmless molds growing alongside more dangerous molds, leading to an ambiguous mold situation. Your test may identify a harmless mold when in fact a dangerous mold is present.
Because of the focus on a certain type of harmful, toxic black mold, homeowners may be inclined to overlook other varieties of non-black mold, but these lighter-colored molds may also cause health problems. Similarly, not all black molds need professional remediation; some can be addressed by any homeowner with a simple diluted bleach wash. However, in order to determine which kind of mold you do have, a professional mold sampling is not a bad idea. Professionals will have the best knowledge of where mold may be hiding, and they will be able to take a more accurate sampling. One way that they might do this is by taking a more extensive sampling of mold from the site and using a microscope to identify the types of mold that are growing. This is generally more comprehensive and accurate than taking a culture.
One thing to be aware of is that where one mold thrives, the conditions for mold in general are good. Even if you have a harmless mold variety that's easy to treat, it's a good idea to address the humidity that the mold is feeding off of so that more molds don't take up residence in your home.