Would prefer as Barb says to have both the Free T4 and Free T3 tests. if you do not have them, you might want to request that they be done.
As far as a TSH being 15 yes it is outside of the normal range, and would indicate you are low thyroid. But there is nothing to panic about. It would suggest more testing and the likilyhood that you may be started on thyroid replacment hormone and work to get the proper dosage over time.
But don't stress out over it.
Can you describe symptoms that you are having along with any other test results.
In the USA, if you request your test results they must provide them to you by law. So you can get them. Now a days most HMO's etc seem to have electronic "MY CHarts" or some such thing that you can log in and get test results.
Did the doctor also order Free T4 and Free T3? If so, please post those results and corresponding reference ranges, as well. The TSH indicates that you need an increase in your medication, but it doesn't show the whole picture...
What, if any, symptoms do you have?