Prenatal screening tests are not definitive diagnostic tools. The purpose of these tests is to identify high or low-risk factors for the presence of certain conditions in the fetus. Screening tests do not definitively show whether a disease is present or not; they only indicate the level of risk. Therefore, a high-risk screening result does not mean the baby is sick, just as a low-risk result does not mean the disease is entirely ruled out. Traditional combined, triple, and quadruple screening tests can detect an average of 80-90% of Down syndrome cases and may miss approximately 15%. When these tests are combined with different protocols, the detection rate can be increased to 90-95%. In contrast, cell-free DNA (Fetal DNA) testing is a highly reliable screening method that can detect approximately 99% of Down syndrome cases.