Hi Karen,

According to "Understanding Lab Work in the Childbearing Year" by Anne Frye,
the PKU test should be done after the milk has been in for 48 hours to
allow for sufficient buildup of protein. This is how it is generally done
in our (Boston, Mass.) homebirth community. At the hospitals it is done on
the day of discharge, which is often the day after the birth. There was an
article in the Boston Globe saying that one of the problems with 24 hour
discharge is that the PKU tests wouldn't be accurate (as opposed to when
they were done before 48 hour discharge.) But it is my understanding that
the test wasn't accurate at 48 hours either.

Hope this helps,
Julie Brill, in Bedford, MA USA
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