In prenatal testing for spina bifida, a life threatening disease, a false positive result indicates that an fetus has spina bifida when, in fact, it does not; a false negative result indicates that a fetus does not have spina bifida when, in fact, it does. To detect spina bifida most accurately, physicians should use the laboratory test that has the lowest proportion of false positive results.
Which of the following, if true, gives the most support to the recommendation above?