I hope the test results are good, first and foremost.
As mentioned, calling the office is the only way to know if you have to have an appointment. However, you may want one to go over what the results mean with the doc if you are not familiar with the test(s) and to discuss any follow-up issues, even if the results are good and definitely if something is off on them.

That being said, you can go to the facility that you had the testing done and get a copy of the test results to be released to you, without having to go through the doc or even if it is at the doctor's office. It is your medical record or with the results being a part of it that you can request at any time, asking for specific test results. There will typically not be a fee for just test results to be released to the patient, but some facilities do charge if it is released to the patient and not to the attending physician. The only main problem though that comes with this is that there is no interpretation of the results to know what it necessarily means. But it is your record and can get them whenever you want, it is just a trip to the facility (either go to the department that the test was done or medical records) and sign a release, the results are yours.