How long would the testing lab keep the cards for? I'm thinking DNA testing of all the cards to see if any match to baby June. Any that don't match should be kept private and the testing discarded by the lab, but if there's a match.
But that would be a huge task for a DNA lab.
For Broward county I think I read approx 17000 births per year. So that's 186 babies over a 4-day period. Approximately 50% of those babies are boys, so that's 93 baby girls. Some of those will be underweight. The heel prick test can be redone on the body, along with blood typing. When those results come back that can also narrow down babies who were PKU positive (if that's the terminology) and those of the wrong blood type. So the basic blood typing would narrow down to about 25 baby girls, extended blood typing (as in reality there are far more blood groups than the ones we normally think of) might narrow that down to about 10. Multiply that by the number of counties. Say that comes to about 50 baby girls, most of them will have had follow-up checks at their local clinic.
And that leaves about 10 who have not been going to follow-up checks at a clinic. Compare those ten with tips on the tip line (someone should want $10,000) and you might even be able to narrow it down to one single baby girl.
If the PD can put in the resources, then I believe that getting an ID for baby June is doable.