The IONA® test is suitable for twin pregnancies. However, in dichorionic (non-identical) twins, the test sensitivity is reduced from >99% to about 95%. The IONA® Software for analysis uses a specific proprietary algorithm iteration for dichorionic twins, but it will not distinguish which twin is high risk.
Fertility Assisted Pregnancies
The IONA® test takes into account the mothers age and when combined with the DNA result it gives a probability of a fetus being affected. For most fertility treatments that include a donor egg or surrogate, it is important to take into account the age of the egg donor not the mother. The IONA® test does this to give the most accurate screening result.