Routine blood tests

[Heather916x]

Hi I was wondering if anyone could help me. I had my routine blood tests done at my first midwife appointment and I got the results last week at my first scan. Everything had come back normal apart from they wasn't sure if I was immune to rubella so had to have a repeat done they said if it come back I wasn't immune then they would give me the injection after I give birth. I had the same problem when I had my son 5 years ago (I should of been immune but it showed I wasn't so had the injection after I gave birth) i recieved a letter yesterday dating the day after I had my repeat blood test done saying an appointment had been made for me to come and have a blood test on Friday (next week) it don't say why I need to have a blood test just wondering if anyone else has had this? What could my blood test be for when I've already had my repeat done and she mentioned nothing about needing more... A little bit worried