Since the prenatal paternity testing on maternal blood is a relatively new technology comparing to CVS or amniocentesis,
there exist some misconceptions that have been picked up by other websites. This section will help you to understand more
about this modern DNA technology.
1. "Fetal DNA and fetal cells are the same things."
No, they are two different things. Fetal cells in the maternal blood is a rare event and to use them as the source of genetic material
for prenatal paternity testing is challenging work (Samura et al, 2000). In contrast, fetal DNA (cell-free DNA) is constantly circulating in
maternal blood during the pregnancy in relatively high concentration (from 3% to 12% comparing to a total DNA in the maternal blood).
2. "The probability of getting any fetal DNA from the blood sample is too low."
As mentioned above, relatively high concentration suggests that fetal DNA could be robustly detected in maternal blood using
modern molecular technology. This point has been confirmed by many research groups that have reported a close to 100% sensitivity at
detecting fetal DNA from maternal plasma. (Honda et al, 2001; Wei et al, 2001; Zhong et al, 2001)
3. "Previous pregnancies may affect test result as fetal cells have been shown to remain in maternal blood even 20 or more
years after pregnancy."
Yes, if the test is done on the actual fetal cells, there is small probability of contamination from previous pregnancies that
can affect the final test result. By serial monitoring of women following delivery, scientists have shown that fetal DNA
is cleared very rapidly from the maternal blood after the delivery, with a half-life time in order of minutes (Lo et al, 1999). These results
indicate that unlike fetal cells in maternal blood, plasma fetal DNA analysis is not complicated by the effects of persistence from
prior pregnancies.
4. "The procedure has not been validated by the DNA paternity testing industry."
Testing on fetal DNA in maternal blood has been highly validated by the scientific community during many years as well as
by a number of DNA diagnostic laboratories (see references).
5. "How the non-invasive technique compares to the invasive testing."
To understand the differences in the procedures, please review the following webpage:
Comparison Table.
6. "How to order the prenatal paternity or gender test?"
This website is designed to simplify the process of ordering. For detailed instructions and more information about
proceeding with the order, please visit corresponding links:
Prenatal DNA Paternity
Prenatal DNA Gender
References
Honda H, Miharu N, Ohashi Y, Ohama K. Successful diagnosis of fetal gender using conventional PCR analysis of maternal serum.
Clin Chem 2001; 47: 41-46.
Lo YMD, Zhang J, Leung TN, Lau TK, Chang AM, Hjelm NM. Rapid clearance of fetal DNA from maternal plasma. Am J Hum Genet
1999; 64: 218-224.
Samura O, Pertel B, Sohda S, Johnson KL, Sekizawa A, Falco VM, Elmes RS, Bianchi DW. Female fetal cells in maternal blood: use of DNA polymorphism to prove origin. Hum Genet
2000; 107: 28-32.
Wei C, Saller DN, Sutherland JW. Detection and quantification by homogeneous PCR of cell-free fetal DNA in maternal plasma.
Clin Chem 2001; 47: 336-338.
Zhong XY, Hahn S, Holzgreve W. Prenatal identification of fetal genetic traits. Lancet 2001; 357: 310-311.
Additional information: read an article in the Science magazine about the non-invasive prenatal technology.
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