Wa'alaikum assalam! PDG test dengan OPK tu berbeza lah, OPK check LH surge (masa ovulation), tapi PDG test check progesterone level after ovulation dah lepas, so confirm kalau ovulation betul-betul terjadi. Kena beli test kit khusus untuk PDG (ada jual kat pharmacy atau online), tak boleh pakai OPK je. A few of my mum friends yang struggle nak conceive guna both together, OPK untuk predict ovulation, then PDG test around 7 hari lepas ovulation to confirm. Best approach is timing intercourse based on OPK, then PDG test to verify, especially kalau cycle tu irregular.