Trisomy test

TRISOMY test: new screening test for detecting Down syndrome and other chromosomal abnormalities with high accuracy

What is TRISOMY test?

TRISOMY test is a non-invasive high-precision screening test based on maternal blood which is used to determine the presence of frequent fetal chromosomal abnormalities as early as in the 11th week of pregnancy.* TRISOMY test detects the risk of trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). It can also determine the sex of your unborn baby.

Posing no risk to either mothers or their unborn babies, TRISOMY test can identify potential false positive results in prenatal biochemical screening, minimising the number of amniocenteses.

What kind of abnormalities can be detected with TRISOMY test?

Down syndrome — trisomy 21

Down syndrome is caused by trisomy 21 – a disorder resulting from the presence of an extra chromosome 21.

Only two thirds of Down syndrome pregnancies will end in a normal childbirth. Approximately 30 % of the pregnancies will end in miscarriage.

This disorder has a serious impact not only on the baby’s overall growth and well-being, but also the shape of its body. It is characterized by distinct facial features and different levels of psychological and mental dysfunction. The most frequent complications include immune and circulatory disorders or gastrointestinal disturbances. Children suffering from trisomy 21 require special health care depending on the extent of their disability. In some cases, Down syndrome symptoms can be moderate and the patient is able to enjoy a relatively long life.

Edwards syndrome — trisomy  18

Edwards syndrome occurs as a result of an extra chromosome 18. The consequences of this chromosome abnormality are serious – the baby is born with low birth weight, an abnormally shaped head, a small jaw, a small mouth, frequently with a cleft lip or cleft palate. In addition to suffering from breathing and feeding problems, the baby is also prone to develop heart diseases. The prognosis is very unfavourable.

Edwards syndrome pregnancies are accompanied by a high risk of miscarriage and a majority of live-born children do not live beyond one year.

Patau syndrome — trisomy  13

The trisomy of chromosome 13 is called Patau syndrome. Trisomy 13 is a serious genetic disorder which can affect all organs, including the brain, heart and kidneys. These children are sometimes born with a cleft palate or deformed limbs. Individuals suffering from this congenital disorder have a very small chance of survival.

Patau syndrome pregnancies are characterized by a high risk of miscarriage or still-born babies.

Who we recommend the TRISOMY test?

TRISOMY test is suitable for any pregnant woman from the 11th week of pregnancy.

Compared to traditional screening methods, TRISOMY test has higher sensitivity and specificity rates for the detection of the trisomy types it is designed to monitor. As a result, it provides a significantly lower number of false positive results.

It is particularly suitable for pregnant women:

  • who have concerns about their baby’s potential disability as a result of one of the trisomy types monitored;
  • who are 35 or older at the time of childbirth and whose biochemical screening test results were negative (combined test, triple test, serum integrated test, integrated test);
  • who conceived as a result of IVF;
  • with positive biochemical screening results, which have to be confirmed by further testing (amniocentesis);*
  • whose ultrasound screening test results suggest a higher risk of the trisomy types monitored,*
  • who have already carried babies with a chromosomal abnormality before,*
  • whose parent(s) has/have been diagnosed with Robertson balancing translocation (an increased trisomy 13 or 21 risk),*
  • pregnant women who have suffered recurrent miscarriage.*

* The screening test must be preceded by a genetic consultation.

TRISOMY test results

Non-invasive prenatal test results provide information about a selected number of the most frequently occurring genetic chromosomal disorders (up to 85 % of all fetal genetic disorders). It must be borne in mind that they cannot identify all existing genetic or developmental disorders.

If negative, NIPT test results can help you avoid invasive diagnostic testing, such as amniocentesis, which carries certain risks associated with amniotic fluid sampling.

The sensitivity and specificity of the TRISOMY test is more than 99 %.

Please note: Despite its high sensitivity and specificity in detecting fetal chromosome 21, 18 and 13 trisomy, TRISOMY test is considered a type of screening, not a diagnostic method. Consequently, a positive result must always be confirmed by amniocentesis or chorionic villi sampling.

A negative TRISOMY test result need not be confirmed by diagnostic amniocentesis, which means, in most cases, that the mother-to-be can avoid invasive tests and the risks they come with.

In the event that your TRISOMY test result is positive, you should arrange an appointment with a specialist in genetics, who will refer you for examinations required in the circumstances.