Comparing data in pivot table grouped by month

Hello everyone,

I apologize in advance if this is something obvious (that I'm missing).

I have a pivot table that groups monthly the number os lab exams that need to be redone due to certain circunstancies. I'd like to be able to generate another table where I could show the ones that increased from previous month (and by how much they increased), so the people at the lab can append information on what could have caused such changes.

Is there any way of doing that?

TIA, Marcelo