Deductions & credits

How do you know if your high deductible health plans is pre-tax or after-tax

My employer automatically takes my insurance premiums out of my paycheck.

I see on my W2 box 12 the code of DD and the dollar amount.

This is printed on page 2 of the W2 "DD—Cost of employer-sponsored health coverage. The amount
reported with code DD is not taxable."

 

does that not taxable statement mean not to tax it because it has already been taxed?

Which should mean I can take the Georgia deduction.

 

Or does it mean not taxable because don't take because it is pre-taxed money and should not be taxed.

Which should mean i can not take the  Georgia deduction.

 

Thanks for your help.