WEDNESDAY, May 2 (HealthDay News) -- A new test, based on single-nucleotide polymorphisms, that only requires a maternal blood sample can correctly identify paternity as early as 8 weeks' gestation, according to a letter published in the May 3 issue of the New England Journal of Medicine.
Xin Guo, Ph.D., from Ravgen in Columbia, Md., and colleagues collected blood samples from 30 pregnant women at 8 to 14 weeks' gestation and compared the genetic profile of fetal DNA in maternal blood with two samples of blood: one from the biological father and one sample from an unrelated man. To prevent the release of maternal DNA into the plasma, a fixative was added to the maternal blood samples. Use of single-nucleotide polymorphisms to distinguish fetal DNA from maternal DNA allowed short amplicons to be utilized, thereby minimizing allele dropout. For each pregnant woman, the three samples were processed in a blinded fashion.
The researchers found that the test correctly identified the father in all 30 cases. They note that the probability of identifying all 30 fathers correctly was less than one in a billion.
"Our approach shows that noninvasive prenatal paternity testing can be performed within the first trimester with the use of a maternal blood sample," Guo and colleagues conclude.
Several authors are employees of Ravgen, which supported the study and holds patents and has patents pending for the methods described in the study.