Qlik Desktop How to take a difference Between last value and previous

[aj_954]

Hi I have a data field called "TotalItems"

I want to make a KPI that shows the difference between the last value in the vector TotalItems and the one previous to it. How do I do that? 

[Rohan]

Hi,

how are you defining Last value ? Does it mean Last value in the table or the Value of the latest record based on some timestamp field ?