All employees must pay Medicare tax, and employers withhold a portion of your payment and submit it to the government for you. Your employer also matches your contribution. This is not a medical expense, but rather a tax.
When you are entering your W-2 into the TurboTax program (you may also be able to import the information directly into the program), just transfer all of the information from your tax document into the associated boxes you'll see in the TT program. When you have completed entering your info, select "Done".