Newborn screening repeated?

Celeste • Pregnant with baby #1 EDD April 3rd, 2016!
Help please I'm freaking out. We received a letter in the mail from health and senior services saying our sons newborn screen needs repeated. He had his 2 month check up today and we took him to have newborn screening repeated. His DR called (I missed the call) and said it needs to be repeated again but didn't say why. Office is closed til Monday. Should I be worried???