I Have Had Three Tb Test Done Since June 2015

I have had three tb test done since June 2015 due to job changes and an internship. Now my part time job is requiring me to get a 2nd step tb test done and this means that I would have two tb test done in the month of October and a total of 4 tb test done since June 2015. I am worried about what all of these tb test might do to my system.