Whats the IME number?

I’m trying to book my medical appointment and the website asks me for an IME number.
Here is a screenshot of the form.

Anyone know what the IME number is?

Are you scheduling an upfront medical?
This will be generated once you give your exam. Check with the doctor/clinic.

Yes, I am. But the website is asking me to enter the number before I go to the clinic. I’ll check with the clinic.