prenatal paternity testing FYI only

Is possible with reduced sensitivity and specificity and a success rate of 70%

Detecting Fetal Cells

There are some companies that claim that they can perform non-invasive prenatal paternity testing. These tests can allegedly determine the paternity of an unborn baby very early in the pregnancy. Some companies claim the procedure can be done at 12 weeks into the pregnancy.

This type of testing is built around the discovery that a few fetal cells as well as fetal DNA could enter the mother's bloodstream during pregnancy. Studies are currently underway to determine the best methods of separating the fetal cells or DNA from the mother's blood, which can then be used in a paternity test.

Scientists and medical professionals identified two main concerns about the immediate applicability of current techniques to commercial paternity testing. According to Dr. B.W. Bianchi, a prenatal geneticist at Tufts University School of Medicine, fetal DNA does enter the mother's bloodstream, but it could linger there for up to 20 years. Fetal DNA lingering in the mother's blood stream after pregnancy would affect the results of prenatal paternity and gender testing.

Further, this type of non-invasive prenatal testing is based on the assumption that enough fetal cells can be routinely extracted from the mother's blood. However, there are no guarantees. The most recent studies have achieved success rates of only about 70%.

Non-Invasive Prenatal DNA Paternity Testing

Introduction to the Non-Invasive Prenatal DNA Paternity

The current available techniques for prenatal diagnosis (CVS and amniocentesis) are invasive and carry with their use a small but significant chance of miscarriage. As a result, the current standard care offers an invasive prenatal test only to those women whose risk of chromosomal or genetic abnormalities are greater than or equal to the risk of a procedure-related loss. The recent discovery of the presence of fetal DNA and fetal cells in maternal blood has offered new approaches to non-invasive prenatal diagnosis. The concentration of fetal DNA in maternal blood was found to be much higher than that present in the cellular fraction. By analyzing DNA profiles based on sets of specific markers, the laboratory is able to compare fetal DNA with genetic profiles of the mother and alleged fathers. This webpage explains in details how and when you can do the non-invasive prenatal paternity test.

Advantages of fetal DNA analysis in the maternal blood

1. Analysis of fetal DNA and fetal cells in maternal blood samples is a screening test that is a non-invasive prenatal procedure and poses no risks to the mother or the fetus. The non-invasive prenatal DNA paternity testing is based on the comparison of genetic profiles of the fetal DNA, mother's blood and samples from the alleged fathers.

2. This prenatal non-invasive DNA paternity testing is relatively inexpensive in comparison to invasive techniques such as CVS or amniocentesis.

To learn more, read Misconceptions about the technology and An article in the Science magazine about the non-invasive prenatal technology.

Timing for the test

Using DNA test from Prenatal Genetic Center, prenatal DNA paternity can be performed after the 14th weeks of gestation.

Results

The procedure takes 12 business days, and the final report contains one of the following results:
- The Alleged Father cannot be excluded as the biological father of the fetus based on the samples submitted from the mother and the alleged father and the DNA extracted from the population of fetal cells;
- The Alleged Father is excluded as the biological father of the fetus based on the samples submitted from the mother and the alleged father and the DNA extracted from the population of fetal cells.

Sensitivity and specificity of the test

Sensitivity and specificity of the detection of cell-free fetal DNA at 14 weeks of gestation for properly collected maternal blood samples is more than 99%. We strongly recommend testing all alleged fathers that are involoved in your case.