A lot of it has to do with the primary insurance (the parents), like if they need to see a specialist but their insurance requires a referral from their primary then they have an extra step in the process or sometimes they can only be seen by certain providers. The schools insurance will sometimes cover the rest of the bill or sometimes just a percentage, depending on what is needed and what kind of coverage the school pays for. Normally for imaging, and Xray will be covered 100% but an MRI or CT scan may cover 50%-75% of whatever is left. As far as surgeries, I've seen anywhere from $500 to $4,000 paid by the schools insurance. Anything with insurance is always hard to be exact.
A lot of times it's the primary insurance that causes the biggest hurdle for kids to get the care they need. They have to do what their primary requires and then the schools will cover as much as possible, but it's not always 100%.
