Complex sentence: The first DNA test has to be performed before the file enters PGN since the US embassy has an agreement with PGN that no adoptions for US residence can be approved before an DNA test has proven the child's identity.
Split into simpler sentences: The first DNA test has to be performed before the file enters PGN. The US embassy has an agreement with PGN that no adoptions for US residence can be approved before an DNA test has proven the child's identity.