To enter it into Turbo Tax:
Go to Deductions & Credits.
Select I'll choose what I work on.
Go down to Medical.
Select Start or Update by Medical Expenses.
Click Yes if your total medical expenses are more than 10% (7.5% if over 65).
Input your medical expenses by category.
Continue till you get back to the Deductions & Credits screen.
For the 10% limitation of your AGI, it's anything that's above 10% of your adjusted gross income.
Adjusted gross income: $50,000 * 10 % (7.5% if you're under 65) = $5,000.
Anything above the $5,000 you can deduct, provided you beat the standard deduction.
You DON'T have to subtract anything though, Turbo Tax does that for you.
Put your TOTAL medical expenses in, and your total income, and the program figures your deduction.