A neuropsych exam is a comprehensive set of standardized tests based on age. Many of these tests are given as part of a special education evaluation by the school psychologist. Having it done privately by a licensed professional can provide you with diagnoses and an interpretation of the testing beyond what school personnel are trained to do. However, a school must simply “consider” the outside testing, they do not have to implement any of its recommendations. Additionally, the school has the right to do their own testing. This means that if your child does not yet have an IEP and you get outside testing and present it to the school, they must hold a meeting within 10 days of receiving it. At that meeting, after going over the testing, they will typically say, “the district needs to do its own evaluation”. They then have 5 days to get you the consent to evaluate. After you sign the consent and return it, the school then has 45 school days to evaluate and hold a meeting for eligibility. This is a long time to wait. Additionally, your child can only take most tests once per year, which means that the school then needs to find tests that were not used in the neuropsych, which their personnel are less familiar with, to administer to determine eligibility.
In my opinion, if you are thinking about getting a neuropsych done, and your child does not have an IEP yet, it is best to request special education testing to be completed at the same time. This way, you can have their testing completed when you get the report from the neuropsych and have one meeting to review all the testing at the same time and use all the testing to determine eligibility.
If your child already has an IEP and you are looking to have a neuropsych, there is no need to do the testing simultaneously.