TRISOMY test is designed to exclude the most frequent genetic disorders (trisomy) of chromosomes 21, 18 and 13, which cause Down, Edwards and Patau syndromes, respectively. Before you decide to go ahead with the test, consult a specialist in gynaecology and obstetrics or a clinical geneticist.
2. Blood sampling
TRISOMY test can only be performed from the 11th week of pregnancy onwards* and blood samples are collected on an empty stomach. Foetal DNA circulates in maternal blood as early as in the first trimester of pregnancy. This foetal DNA can be isolated using a special laboratory procedure based on a 10ml sample of maternal blood. Blood samples are taken by a female nurse at the doctor’s office, whereupon they are sent to the laboratory to be processed and prepared for analysis.
TRISOMY tests are mostly performed between the 11th and the 22nd week of pregnancy. Choosing the earliest/latest date possible is a decision that generally depends on the pregnant woman’s preference and her physician’s recommendation based on the patient’s health condition.
* In compliance with a resolution adopted by the Ethics Committee of the Slovak Ministry of Health, our laboratory only provides test results to patients once they have completed their 12th week of pregnancy. The test result is disclosed and interpreted to the patient by the doctor who referred the patient for the test.
The payment of a TRISOMY tests depends on the country specification.
4. Laboratory blood analysis
As soon as the payment has been identified, the sample is analysed using a special method.
1. Blood sample processing
Blood contains a liquid component (plasma, which is yellow) and blood corpuscles (white blood cells, red blood cells and platelets). TRISOMY test is based on analyzing blood plasma, which is separated from blood corpuscles under laboratory conditions.
2. Plasma cleaning
Free circulating DNA is obtained from plasma samples using a multi-step cleaning procedure – including the DNA that comes from the foetus. Undesirable proteins and other chemical substances are all removed in the process.
3. Preparing DNA samples for analysis
For the purposes of the test, the isolated DNA has to be prepared using a special laboratory process that is called “sequencing library preparation”. This procedure takes about 2 days and involves DNA replication because our experts need a much larger quantity of DNA material compared to what they are able to recover from maternal plasma samples.
4. Sample quality control
TRISOMY test is a costly and time-consuming test whose outcome depends on the quality of the prepared samples for analysis. To make sure it was well-prepared in the laboratory, the “sequencing library” must be checked using special equipment before it is subjected to sequencing analysis.
5. Final analysis – sequencing
If the prepared sample has passed the quality control test, it is ready for sequencing analysis. By reading 30 million fragments over a period of 20 hours, the laboratory staff see if the given foetus is affected by any of the monitored trisomy types.
6. Test outcome
Test results are sent from the laboratory directly to the physician who referred the patient for the test in the first place. Respecting the doctor’s position as a health care provider, the laboratory will not provide any test results directly to the patient.
5. Delivery of test results
The doctor who suggested the screening test informs the patient about the result of the test. The laboratory cannot provide the results directly to the patient (respecting the doctor’s position as a health care provider).
Praise for TRISOMYtest
I was more than satisfied with the test! I received my test results within 5 days and I knew exactly what to expect. What's more, the test will tell you whether you're expecting a boy or a girl. I recommend the test by all means!