parents do the medical exam without the UMI?

[8221129]

I got the email to imform me the sponsorship is approved and my parents need to do the medical exam. There is no form or UMI number in the email. Some friends have to wait for a couple of months to get the another email from visa office with the UMI number or the exam form. Some friends said we can go to the hospital and do the exam and do not wait for that email with UMI. The hospital will create a UMI and email the report with UMI to the visa office.
Can we do it that way?

Thanks