Trying to add a value if a test result is positive or negative

Hello,


I have been asked to build a spreadsheet to calculate patients follow up depending on their blood test result.
I will only know if the result is Positive or Negative, so I have a column with a dropdown option for either of those results. If the result is positive I need the next column to calculate a day 61 days from the original test, if its negative then I need it to give me the date a year from the original test.

Halp anyone?!