G-TEST PRO is a non-invasive prenatal screening test for fetal chromosomal abnormalities
G-Test PRO
The G-TEST® PRO is a non-invasive prenatal test for screening for fetal chromosomal abnormalities.
The test assesses the fetus’ risk of a chromosomal abnormality early and with high accuracy
The G-TEST® PRO is a safe and reliable prenatal test, as it requires only a simple maternal venous blood draw and poses no risk of miscarriage or infection. It can be performed early, starting from the 10th week of gestation, and provides rapid results, usually available within about 5 working days.
Thanks to its high sensitivity and specificity, both greater than 99%, the test guarantees a high level of accuracy. Unlike many traditional approaches, it is comprehensive, as it allows the detection of aneuploidies across the entire chromosomal set. Moreover, it is certified, being based on a CE-validated bioinformatics analysis that ensures the reliability of the process.
In addition, the G-TEST® PRO is supported by the availability of free genetic counseling and reimbursement for further diagnostic investigations if needed, making it not only a cutting-edge tool, but also a test designed to offer reassurance and complete support throughout pregnancy.
What the G-TEST® PRO evaluates
G-TEST® PRO is available in 4 options, all offering the same level of resolution and, consequently, the same quality of analysis.
They differ only in the number of chromosomal abnormalities screened, ranging from the most common trisomies to deletion syndromes.
Specifically:
| Detectable Anomalies | Trisomies | XY* | Deletions | WGA |
|---|---|---|---|---|
| Down Syndrome (T21) Edwards Syndrome (T18) Patau Syndrome (T13) |
✔ | ✔ | ✔ | ✔ |
| Turner Syndrome* Klinefelter Syndrome* Jacobs Syndrome* Triple X Syndrome* |
✘ | ✔ | ✔ | ✔ |
|
1p36 deletion syndrome
2q37 deletion syndrome 2q33.1 deletion syndrome Dandy-Walker syndrome Wolf-Hirschhorn syndrome Cri du Chat syndrome 7q deletion syndrome 7q11.23 deletion syndrome Langer-Giedion syndrome 9p deletion syndrome DiGeorge syndrome 2 WAGR syndrome (11p13) Jacobsen syndrome Angelman syndrome Prader-Willi syndrome Levy-Shanske syndrome 16p12.2-p11.2 deletion syndrome 16p13.3 deletion syndrome Smith-Magenis syndrome Miller-Dieker syndrome 17p13.3 duplication syndrome Potocki-Lupski syndrome Yuan-Harel-Lupski syndrome 18p deletion syndrome Alagille syndrome 1 DiGeorge syndrome |
✘ | ✘ | ✔ | ✔ |
| Trisomy 22 – Trisomy 16 – Trisomy 9 | ✔ | ✘ | ✔ | ✔ |
| Deletions / duplications on all chromosomes | ✘ | ✘ | ✘ | ✔ |
| Rare autosomal aneuploidies | ✘ | ✘ | ✘ | ✔ |
| Y chromosome detection (fetal sex) | ✔ | ✔ | ✔ | ✔ |
(*) Not available for twin pregnancies
How the G-TEST® PRO is performed
By contacting Bioscience Institute filling out the G-TEST® PRO request form, it is possible to receive all preliminary information (timelines, execution procedures, etc.) as well as details on the nearest affiliated centers where the test can be performed.
The maternal peripheral blood sample required for the G-TEST® PRO is approximately 8 ml.
The G-TEST® PRO can be performed from the 10th week of gestation using the CE-IVD certified collection tube provided in the sampling and transport kit.
Samples are sent to the Bioscience Genomics laboratories, where the blood arrives inside an isothermal kit designed for the transport of Category B biological substances, in compliance with UN3373 regulations.
Test reliability - Sensitivity and specificity greater than 99%
All G-TEST® PRO options are based on a high-resolution sequencing protocol (25 million reads). This ensures the ability to detect abnormalities across the entire chromosomal set while maintaining a high level of accuracy.
| Type of Abnormality | Sensitivity | Specificity |
|---|---|---|
| T21 (Trisomy 21, Down Syndrome) | >99.17% | >99.95% |
| T18 (Trisomy 18, Edwards Syndrome) | >98.24% | >99.95% |
| T13 (Trisomy 13, Patau Syndrome) | >99.9% | >99.96% |
| Sex Chromosome Aneuploidies | >99.6% | >99.8% |
| Deletions / Microdeletions | >99% | >99% |
| Whole-genome analysis >7Mb | 99% | >99% |
| Fetal sex | >99% | >99% |
The introduction of new computational algorithms makes the G-TEST® PRO extremely reliable, even in detecting small abnormalities.
The DELETIONS panel, in fact, includes 26 deletion, duplication, and microdeletion syndromes (including DiGeorge syndrome), selected among the less rare and most clinically significant ones.
Why choose the G-TEST® PRO
Discover the advantages of the prenatal test offered by Bioscience Genomics
The G-TEST® PRO is a next-generation prenatal test that provides essential information about the genetic health of the fetus, with no risk to the mother or baby throughout the entire pregnancy.
Through a simple maternal blood draw, it delivers rapid and highly accurate results. Here are the main advantages:
- It is based on a maternal blood sample, therefore it poses no risk to the pregnancy
- It can detect abnormalities in all chromosomes, including in twin pregnancies
- The G-TEST is entirely performed in the Bioscience Genomics laboratories
- Results are available in approximately 5 working days
- The DELETIONS panel can detect 26 deletion, duplication, and/or microdeletion syndromes with >99% accuracy
- Sensitivity and specificity are on average greater than 99%
When is the G-TEST® PRO recommended?
Pregnancies in which invasive tests are contraindicated
Pregnancies in which invasive tests are not intended
Singleton or twin pregnancies
Singleton pregnancies conceived through assisted reproduction (including egg donation)
Twin pregnancies conceived through assisted reproduction (including egg donation)
In-depth Information
Would you like to explore further or learn more? Access comprehensive explanations by expanding the sections below.
Information about the G-TEST® PRO results
Information about the test results
To date, more than 3 million G-Tests have been performed in over 52 countries.
Once it reaches the Bioscience Genomics laboratories, the blood sample is processed by the laboratory biologists and the results are ready in approximately 5 working days.
It is important to note that the timeframe may vary: the analysis includes a series of rigorous quality controls to ensure the reliability of the result, including verification of the amount of fetal DNA present in the blood sample, which varies from one expectant mother to another. In some cases, a low amount of fetal DNA or poor sample quality may require the analysis and/or the blood draw to be repeated.
If it is necessary to repeat the test due to insufficient fetal DNA concentration in the maternal blood, the repetition will be free of charge.
About Prenatal Diagnosis
About Prenatal Diagnosis
Prenatal diagnosis refers to the set of instrumental and laboratory investigations through which it is possible to monitor the health and well-being of the fetus during pregnancy.
The use of prenatal diagnostic techniques aims to identify fetal conditions of genetic, infectious, iatrogenic, or environmental origin.
At present, only certain fetal conditions can be detected, but prenatal diagnosis is making great strides forward, allowing us to look to the future with greater possibilities. The various techniques currently available make it possible to detect some multifactorial malformative conditions, chromosomal abnormalities, and genetic diseases for which the specific defect is known, as well as the presence of infectious agents in the genome.
Prenatal diagnostic techniques can be either non-invasive or invasive, depending on whether or not they involve a risk of miscarriage.
Non-invasive methods are procedures that assess the risk of chromosomal abnormalities. They are defined as non-invasive because, being based on ultrasound evaluations and/or maternal blood analysis, they pose no risk to either the mother or the fetus. Their purpose is to detect fetal chromosomal abnormalities, thereby limiting the need for invasive testing. The G-Test® is the most innovative of the non-invasive tests; it is performed on fetal DNA, ensuring both safety and reliability.
Invasive methods involve the collection of tissue samples, through amniocentesis or chorionic villus sampling, with a miscarriage risk ranging between 0.5% and 1%, followed by analysis to determine the presence of genetic abnormalities using different techniques depending on the diagnostic requirements.
About Chromosomal Abnormalities
About Chromosomal Abnormalities
The human chromosomal set consists of 46 chromosomes organized into 23 distinct pairs. Aneuploidies are abnormalities in chromosome number.
These abnormalities may result in the presence of an additional chromosome (trisomy) or the absence of a chromosome (monosomy). Deletions, on the other hand, occur when a segment of a chromosome is missing, along with the genes located on that chromosomal fragment.
Trisomies
Trisomies are characterized by the presence of an extra chromosome in addition to the normal chromosomal pair. The most common at birth is Trisomy 21, associated with Down syndrome (frequency 1 in 700 live births). Less common are Trisomy 18 (Edwards syndrome, 1 in 7,900), Trisomy 13 (Patau syndrome, 1 in 9,500), Trisomy 22, Trisomy 16, and Trisomy 9, which are even rarer and are usually associated with early miscarriage, intrauterine or perinatal death, or, in any case, very limited life expectancy.
Sex Chromosome Abnormalities
Sex chromosome aneuploidies are characterized by the absence of a sex chromosome, as in Turner syndrome (45,X – frequency 1 in 2,500 females), or by the presence of an extra sex chromosome, as in Klinefelter syndrome (XXY, frequency 1:500 to 1:1,000 males), Jacobs syndrome (XYY, frequency 1 in 1,000 males), and Triple X syndrome (frequency 1 in 1,000 females).
Deletions and Duplications
These are unbalanced chromosomal abnormalities characterized by the absence of a chromosomal segment (or the presence of additional copies of the same fragment) and, consequently, the loss or duplication of the genes located on it. Such alterations cause syndromes of variable clinical significance depending on the chromosome involved, the specific region, and the size of the deleted or duplicated segment.
Some deletions cause rare syndromes, which may be associated with: congenital heart defects, facial dysmorphisms and cleft lip/palate, feeding difficulties in early infancy, gastrointestinal and immune system dysfunctions, intellectual disability, or neurocognitive developmental delay.
At present, these types of chromosomal abnormalities cannot be identified with a traditional karyotype analysis of chorionic villus cells or amniotic fluid.
Main Deletions
-
Cri-du-chat syndrome
-
1p36 deletion syndrome
-
2p33.1 deletion syndrome
-
16p12 deletion syndrome
-
Jacobsen syndrome (11q23 deletion)
-
Prader-Willi/Angelman syndrome (15q11.2)
-
DiGeorge syndrome 2
-
Van der Woude syndrome
