Usually not, but what you often need is a mold inspection.
A mold inspection can typically determine the source of unwanted mold growth and provide you with a written solution, without air testing. Additional add on costs for mold testing often not needed. The EPA, CDC and the CDPH all recommend against mold testing, rather they recommend fixing the problem safely.
Mold testing only makes sense if you are not sure where the mold is coming from, or you have a medical condition related to mold exposure. Do not be pressured into mold testing when it is not needed. “Mold inspectors” are often poorly trained and think that mold testing is always needed (it also makes more money for them).
Always look for a mold inspector that is certified by ACAC. You can find such an inspector on their website at ACAC.org; these inspectors are properly certified in the inspection process. But even they may try and up sell you on unneeded testing.