Her doctor will not worry about this because it is slightly elevated. If it continues to rise then there are 2 sources- liver or bone.
Reta
If the rest of her blood work looks good then I wouldn't be too concerned over this mild alkaline phosphatase elevation.
But, I'm not a doctor or in the medical field in any capacity so, if you and/or she is concerned, see a doctor and get an expert opinion.
Good luck,
Mike