What do the results of the NIPT test mean?

What do the results of the NIPT test mean?

The results of Non-Invasive Prenatal Testing (NIPT) can have varying ramifications depending on whether they are positive or negative.

1/ Negative/Low Chance Results

A low chance NIPT result implies that the test did not find any serious chromosomal abnormalities in the foetus that were screened for. This result provides confidence to pregnant parents, showing a lesser likelihood of specific conditions like Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), Patau syndrome (Trisomy 13), and other chromosomal abnormalities that may be included in your test. However, it's crucial to note that a negative result does not guarantee the absence of all genetic disorders or birth abnormalities.

2/ Positive/High Chance Results

A high chance NIPT test shows that there may be an increased risk of a chromosomal disorder in the foetus. It's vital to recognise that a positive result from NIPT is not a diagnosis but rather an indication for additional assessment. In this scenario, expectant parents should discuss the results with their healthcare professional, who may offer a detailed ultrasound examination and/or additional diagnostic tests, such as amniocentesis or chorionic villus sampling (CVS), to confirm the presence of a chromosomal problem. These invasive diagnostic tests can provide more definitive information regarding the foetal chromosomes.

3/ False Positive Results

It's vital to be aware that NIPT, like any screening test, might produce false-positive results. A false-positive result means that the test suggests a high risk of a chromosomal defect when, in fact, the foetus is chromosomally normal. False positives can arise owing to several factors, including biological reasons and technical constraints of the test. In such circumstances, invasive diagnostic testing (CVS or amniocentesis) is required to clarify the true condition of the foetus.

4/ Uncertain Results

In some situations, NIPT results may be described as uncertain or inconclusive. This may arise due to reasons such as low foetal fraction (the proportion of foetal DNA in the maternal blood sample) or other technical limitations of the test. In certain cases, further testing or repeat NIPT may be necessary to acquire a clearer answer.

NIPT tests can reveal foetal chromosomal abnormalities risk. These results must be interpreted with clinical judgment and followed up with appropriate diagnostic testing where needed.