You can visit FMGC in TTDI PJ for this scan. Quite pricey. It cost us 600++ two years ago.

From what I was told, the most accurate test would be First Trimester Test with NT, nasal bone and blood test (sorry if I messed up the data, you can visit the website for exact details). It can be done before your pregnancy exceed 14 weeks.

I also having second thought. My wife gynae suddenly asked if we wanna do double test. We did ask about the First test but he was like it doesn't matter. I rather do the First because its 95% accuracy compared to Double or Triple Test. But I can tell you, the specialist at FMGC very pro. Instead of scaring you, he was quick to calm you down and look at the positive side. Like one of his patient with 1/20 DS but he said his patient got a healthy baby. We tend to look at the negative side too much until overlook the chance for a healthy baby is 19/20.