THE MEANING OF A NON-INVASIVE PRENATAL TEST
There are several options available for prenatal screening. In comparison with TOMORROW Prenatal Test, traditional screening methods have a lower accuracy and a higher false positive/negative rate.
Also, invasive diagnostic testing, such as amniocentesis or chorionic villus sampling (CVS), involve a risk of abortion of 0.5% or 1-2%, respectively.
TOMORROW USES THE MOST ADVANCED TEHNOLOGY AVAILABLE
- From a simple maternal blood sample, circulating DNA fragments can be harvested of both from maternal and fetal origin.
- During pregnancy, small fragments from the fetal-placental unit enter the mother’s blood circulatory system. These DNA fragments are normally described simply as fetal DNA.
- Circulating DNA fragments, both from the mother and the fetus, are analyzed by TOMORROW Prenatal Test.
A CLOSER APPROACH TO DEEP-SEQUENCING TECHNOLOGY
- Maternal and fetal circulating DNA fragments are analyzed through Next Generation Sequencing (NGS) technology.
- Afterwards, the number of sequences correspondent to each chromosome are aligned and analyzed through a complex bioinformatic analysis, using ILLUMINA platform.
- Gender identification (fetal sex) is determined by detecting the presence or absence of Y chromosome in maternal blood.
- Potential aneuploidies are detected by comparing maternal and fetal genomic material to reference values.
TOMORROW PRENATAL TEST PERFORMANCE 1,2
|Observed Sensitivity||Sensitivity Range||Observed Specificity||Specificity Range|
|T21 > Down Sindrome
|T18 > Edwards Sindrome
|T13 > Patau Sindrome
|MX > Turner Sindrome
1Taneja et al., Noninvasive prenatal testing in the general obstetric population: clinical performance and counseling considerations in over 85 000 cases. Prenatal Diagnosis. 2016, 36: 1–7.
2Bianchi et al., Genome-wide fetal aneuploidy detection by maternal plasma DNA sequencing. Obstetrics & Gynecology. 2012, 119(5): 890–901.
WHAT TYPE OF INFORMATION CAN TOMORROW PRENATAL TEST PROVIDE?
TOMORROW Prenatal Test delivers clear information on the most common fetal aneuploidies, which may minimize the maternal anxiety and, in case of a positive result, guide for invasive procedures to have a definitive diagnosis.
- “Not detected”, in case there is a highly reduced probability for the tested aneuploidies;
- “Detected”, in case there is a highly increased probability for the tested aneuploidies.
FREE OF CHARGE CONFIRMATION
In case of a positive result, according to recommendations from ACOG, ACMG and SMFM, confirmation by prenatal invasive diagnosis is advised.
In this case, CGC Genetics provides, at no additional cost: a quick analysis by QF‑PCR, available in 24 to 48 hours, and also chromosome analysis (karyotype), in a fetal sample.
IT IS RECOMMENDED THAT NO IRREVERSIBLE CLINICAL DECISION IS TAKEN UNIQUELY BASED ON THE RESULT OF THIS TEST.
- The test cannot be performed before 10+0 weeks of gestation, as estimated by the date of last menstrual period, CRL or another clinically appropriate method (equivalent to 8 weeks of fetal age, if determined by date of conception).
- The test cannot be considered a diagnostic test, even though all recent publications demonstrate its high precision (~99%) and very low false positive and false negative rates (0.1% and 0.02%, respectively)1.
- False negatives: in rare cases, a tested aneuploidy may be present, even if the test result is of “not detected”.
- False positives: a result of “detected” for a tested aneuploidy may not be present in the fetus but, in reality, is identified only in the placenta.
- Test results of "not detected" do not eliminate the possibility of the fetus having other chromosomal disorders, besides the ones mentioned and within technique limitations (< 1%), birth defects or health problems.
- If the pregnant woman has recently received a blood transfusion, transplantation, cell therapy or immunotherapy, an accurate assessment of fetal DNA will not be possible.