If I need a 3 state bit, like (True, False, and N/A) as a param passed in, can I use null for the 3rd state?

for example, if a param of type bit is needed, can I pass either 0,1, or Null as a value?

Reason being is that this filter has some checkboxes, and dropdowns,

like a checkbox that says include all accounts with/without (with/without is a combobox) an email address

so if its not even checked, i want to pass null to let the SP know to not even need to deal with that part of the filter, and then obviously if they did check the checkbox, a 0 or 1 for true/false for the with/without

or is it just easier to use an int and pass 1 of 3 numbers in to do the check?