Although it was over a year ago that I had this test done, a fellow runner asked for a post on my experience with the pressure test.
The pressure testing, put bluntly, is not a lot of fun. I had anticipated having local anesthetic to help with the pain, but we started the test about 10 minutes after my run, so I did it with full feeling. The anterior and lateral compartments were not too bad - probably slightly more painful than a shot. The posterior compartments, of which there are two, were very painful. Essentially, they have to push through the first compartment to measure the second. Overall, I would give the procedure a 4 to 6 on the pain scale. The pain is bad, but fleeting. Besides some tenderness around the injection site, I had hardly any discomfort post-test.
One of the biggest benefits for me was the immediacy of the results. While an MRI has to be read, the pressure tests can be evaluated immediately. Although I would end up waiting a year for the surgery, having an accurate picture of what was going on in my calf was great.