alkakine phosphatase

my child is 7 months old it was a pre term delivery twins both male. One of them was diagnosed having serum alkaline phosphatase as 422 D/L. Is this normal or a cause for worry?

[AnnieBrooke]

Frankly, it seems like an alkaline phosphatase count would usually be pretty high in a baby.  Alkaline phosphatase is an enzyme made in the liver, bone, and the placenta, and is normally present in high concentrations in growing bone and in bile.  It's released into the blood during injury and during such normal activities as bone growth and pregnancy.  If this test was right after birth, it seems logical that it would be influenced not only by the "growing bone" part of that definition, but also the "placenta" part and even the "injury" part. Even now, his bones are growing really fast.  What did the doctor say about the number?