Hi liting,
u choose which 1 u prefer. So either 1, not both.
Some mummies prefer oscar coz higher accuracy & can test earlier BUT its expensive lor.
Both are blood tests, but Oscar includes a detailed scan which measures the thickness of bb's neck.
Basically the thicker it is, the higher chance of DS.
Both tests give ratio results, eg. 1:1.6 to show how much u are at risk of having a DS bb.
From wat i know so far, oscar sometimes gives a false-positive result, means it says u are high risk when u are not.
After getting the results of either tests, if we still need to be 100% sure, there's an amnio test (100% accuracy) but that 1 hor quite painful.
They put 1 big needle into ur tummy to draw out the 'yang tai shui'. N got chance of miscarriage.
I stil unsure to go for oscar or TT. M checking with KK, see got cheaper or not.
I actually prefer to do it earlier so to set my mind at ease.
Ya lor a lot of price diff hor.
I guess itz coz oscar can do earlier & includes a detailed scan.
I told my gynie i prefer to do earlier so touch wood, if anything i still got time to decide if i wan continue pregnancy.
My gynie says dun worry lah anyway u have up to 24 weeks to abort, got time 1.. I went "HAR!!!!????"