DateDiff every 3days

Hi! im doing DateDiff every 3days I have column 1 [DateAdded], Column2 [DateSent]  every 3days 
This is my code in my sql but its not working please help thanks

DATEDIFF(DateAdded, DateSent)
SELECT RecID ,ClaimID ,Name  ,DateTime ,DateSent DATEDIFF(DateAdded,DateSent) WHERE STatus = 1 and Claimno = @Claimno ...