Taking Harmony NIPT is easy. It requires a simple blood draw and can be taken as early as 10 weeks into pregnancy. It is recommended to do an ultrasound before NIPT to make sure everything else looks good, and if it's twins we have to adjust the analysis accordingly.
While traditional screening (KUB) are performed later in pregnancy and may require multiple office visits2, Harmony can deliver clear answers as early as the first trimester with a single blood draw.
Harmony NIPT gives clear answers about the probability of trisomy 21 (Down syndrome), 18 (Edwards syndrome), and 13 (Patau syndrome). Once the analysis is completed, your provider receives the results and shares them with you. If you also selected analysis of fetal sex, sex chromosomes (X and Y) or 22q11.2 microdeletion, those results are provided as well.
During pregnancy, the mother’s blood contains fragments of the developing baby’s DNA. Harmony is a type of test that analyzes this DNA in a blood sample to predict the probability of trisomy 21 (Down syndrome), as well as trisomies 18 and 13, in the baby.
Harmony is more accurate than traditional screening (FTS = KUB).1 With Harmony, there is less chance your doctor will recommend follow-up testing, such as amniocentesis, due to a false positive result.
While traditional blood tests (first trimester screening = KUB) can miss as many as 15% of Down syndrome cases in pregnant women2, Harmony’s DNA-based technology accurately identifies more than 99% of cases.1
Harmony NIPT specifically targets the DNA in chromosomes 21, 18 and 13. While rare, these are the most common trisomies that occur in babies born to women of any age, when no other risk factors are known.4 The Harmony test also offers the possibility to analyse fetal gender, sex chromosomal aneuploidies and the most frequently occurring chromosomal deletion, 22q11.2. Read more about 22q11.2 deletion syndrome below.
Harmony NIPT incorporates extensive quality controls. These controls include measurement of the amount of the developing baby’s DNA in each sample, to ensure that there is enough DNA present to return a reliable result.3 While it may seem surprising, not all DNA-based genetic tests take the care to measure this basic information.
Harmony NIPT performance
Sensitivitet shows how many of the cases you are looking for (babies with chromosomal abnormality) that you actually find. Should be as close to 100% as possible.
Specificity shows how many of the cases not looked for (healthy babies) that get the right result. The specificity should be as close to 100% as possible, and is associated with false positives (positives responses that turn out to be false).
False positive responses should be as low as possible, preferably close to 0. This is because you don’t want to undergo amniocentesis unnecessarily. Because chromosomal abnormalities and microdeletions are relatively uncommon, this means that a test with poor specificity results in many positive responses being false alarms.
A microdeletion syndrome is lacking a small part of a chromosome and is named after the part of the chromosome that is missing. Harmony NIPT kan look for the 22q11.2 microdeletion, the most common genetic cause of intellectual disability and heart failure after Down’s syndrome.
The advantage of Harmony NIPT is to avoid unnecessary amniocentesis / CVS.
Although the NIPT technologies are very good, a small number of results always appear, which falsely indicates a high probability of abnormality. These false alarms become more frequent the more abnormalities that are analyzed for, and if the abnormality in question also appears extremely rare, which applies to almost all microdeletions (1/10 000 – 1/100 000 births), the result is that the analysis makes more harm than good by causing an increase in the number of unnecessary amniocentesis / CVS.
For example, about 300-400 amniocentesis may be required to identify a true case of a microdeletion that occurs in 1 in 50,000 births. The risk of miscarriage with invasive sampling is around 0.5%, which means that such a test causes more harm than good.
We think this is not reasonable and therefore does not offer a wide panel of extremely rare syndromes with Harmony NIPT.
1. Norton et al. N Engl J Med. 2015 Apr 23;372(17):1589-972.
2. ACOG Practice Bulletin 77. Obstet Gynecol. 2007 Jan;109(1):217-27.
3. Sparks et al. Am J Obstet Gynecol. 2012 Apr;206(4):319.e1-9.
4. Grati FR et al. Am J Med Genet Part A 152A:1434–1442.