By failing to give the false-negative probability, you make the exact answer incalculable.

ECONOMIST: Letters | The

At least one case of a false-negative report also raised questions.

WSJ: New Questions on Cutting-Edge Prenatal Tests

False-negative results, which are rarer, also present a quandary for women and doctors who may not find out until much later that a fetus has an abnormality.

WSJ: New Questions on Cutting-Edge Prenatal Tests