Just as Heather said... I too believe newborn screening do not test for genes at all, rather markers... there is a specific false negative rate but I do not remember what it is.
The only thing that is going to give you close to 100% accuracy will be complete genetic testing... and even that is not 100% as they are identifying new genes all the time - but it's a heck of a good start.
The only thing that is going to give you close to 100% accuracy will be complete genetic testing... and even that is not 100% as they are identifying new genes all the time - but it's a heck of a good start.