My daughter is 10 months old and has PKU. Her level originally was 12 when the newborn screen was done at the hospital 48 hours after birth. By the time the results came back positive for PKU at 8 days of age her level had gone up to 42. They came down relatively quickly after that but since have been as high as 13 and as low as .1. It is very hard for the levels to stay consistent during the first year due to growth spurts, etc. Her levels really go up and down without any change in diet. From what I understand, it is not only how much phe your baby gets per day, but also how fast she is growing that can affect the level. I hope she is doing well now!