"What Happens if the Blood Concentration for Non-invasive DNA Testing is Low?"

Low blood concentration is caused by factors such as incorrect testing time, excessive testing duration, anemia, and other reasons. The specific descriptions are as follows:

1. Incorrect Testing Time: Pregnant women generally undergo testing between the 12th and 24th weeks of pregnancy. If the test is conducted too early, the relatively low concentration of free DNA in peripheral blood can affect the test results, making them generally inaccurate and not meaningful for reference.

2. Excessive Testing Duration: After collecting peripheral blood, the test needs to be conducted within the specified time. If the testing duration is too long, the sample quality may be affected, such as blood cell apoptosis or decreased fetal DNA concentration, leading to abnormal results.

3. Anemia: It can also be caused by maternal factors, such as pregnant women being selective eaters or having dietary preferences, leading to iron-deficiency anemia. The quality of blood collected in blood samples will be affected, resulting in a low number of blood cells and reduced DNA concentration. Other reasons such as hyperlipidemia in pregnant women cannot be ruled out. After discovering abnormal results, a review must be conducted as soon as possible, and amniocentesis can also be used for diagnosis if necessary.