If you have an outstanding student loan and there is a "lien" put on your tax refund for it, it will show on your Notice of Assessment (NOA) as a "Balance Transfer". TurboTax does not show any calculations for debts owed to CRA or other Govt agencies or subtract from your current year refund.
If you have a refund for the current year, TurboTax will say you have a "Tax Refund" and the amount will be shown in green.
If you have a balance owing for the current year, TurboTax will say you have a "Balance Due" (or owing) and the amount will be shown in red.