2-3 weeks seems like a long time but it does depend on where you go. For us:
The request was received on Oct 21st. Appointment was made for the following day. The doc office my partner went to was integrated directly with IRCC so the results were 'uploaded' by the doctor. We did have to wait about 7 days for the xrays to get sent from the radiologist (a different clinic) to the doctor. There was an abnormality on the results which the doctor called and discussed with my partner. They uploaded the results the next day and we had a request to get additional xrays the following day (this was early Nov).
The second set of xrays were completed on November 9th, sent to the doc, they uploaded the results and she had a pass on Nov 12th.
If you're still waiting 2-3 weeks, you may want to call IRCC to see if they've received the results and make sure you didn't need to upload them manually.