while (<>) {
  my @params = split /\s*,\s*/;
  foreach my $param (@params) {
    $param =~ /(Identities|Positives|Negatives)\s+=\s+(.+)\s+\((.+)\%\)/;
    # $1 now contains which type you matched, $2 and $3 are the submatches, do what you will with them
  }
}