What does an inconclusive harmony test mean?

with the Harmony® Prenatal Test. Page 2. Inconclusive Fetal Sex. An inconclusive fetal sex result indicates that the data obtained from the sample did not provide clear evidence of the presence or absence of the Y chromosome.

How common is inconclusive NIPT?

Although genome-wide NIPT reports high sensitivity and specificity rates for fetal aneuploidy, approximately 3-4% of these NIPT results are inconclusive and non-reportable due to either technical or biological failure (e.g. low fetal fraction in maternal serum).

Why would the Harmony test fail?

The most common reason is that there is not enough DNA from the baby/placenta in the blood sample. Having a “no call” NIPT increases the chance that the baby has a chromosome difference.

Can harmony test detect chromosomal abnormalities?

The Harmony® prenatal test is a DNA-based blood screening test for the most common chromosomal abnormalities, including Down syndrome (trisomy 21). Harmony is more accurate than traditional tests and can be performed as early as 10 weeks into pregnancy with just a simple blood test 1,2.

What happens if NIPT is inconclusive?

When the sample does not have clear information to give a reliable result for SCA, the lab reports the result as “inconclusive”. There may still be enough information to predict the fetal sex for some pregnancies. Twin pregnancies do not include testing for SCA conditions.

What causes insufficient fetal DNA?

Reasons for low fetal fractions include testing too early in the pregnancy, sampling errors, maternal obesity, and fetal abnormality. There are multiple NIPT methods to analyze fetal cfDNA. To determine chromosomal aneuploidy, the most common method is to count all cfDNA fragments (both fetal and maternal).

Why do NIPT tests fail?

Another NIPT limitation is the proportion of ‘no-call’ results, i.e. the NIPT fails to return a result in 1–3% of women. The most common cause for this is an insufficient cffDNA fraction, often associated with an increased maternal body mass index.

What causes inconclusive NIPT?

The lab reports the result as “inconclusive” when there is not enough information from the sample to provide a reliable result. number of sex chromosomes from a fetus can be complicated. The Y chromosome is small and can be hard to measure, but the X chromosome can sometimes be even harder to measure.

How accurate are Harmony tests?

Harmony is highly accurate, detecting more than 99% of fetuses with trisomy 21, and more than 95% of fetuses with trisomy 18, trisomy 13 or abnormalities of the sex chromosomes, plus more than 75% of fetuses with 22q11.

Does Harmony test pick up mosaic Down syndrome?

The Harmony test does not provide information on mosaicism, partial trisomies or translocations, or other rare chromosomal abnormalities.

How accurate is the harmony test for trisomy 21?

Why would NIPT be inconclusive?

An inconclusive fetal sex result indicates that the data obtained from the sample did not provide clear evidence of the presence or absence of the Y chromosome.

Can you take the NIPT test twice?

There are many reasons NIPT may not give a result. When the test is repeated, about 1 in 3 repeat NIPT samples comes back with no result. That means whatever caused no result the first time is still interfering with the test. This is unlikely to be a lab mistake.

Can I repeat NIPT test?

Repeat NIPT screening – NIPT may give a result the second time you do testing. You will know within two weeks whether or not repeat testing is successful. Repeat testing is only done once. You will be offered different testing if there is no result from NIPT after a second try.

Is Harmony test more accurate than NHS?

The Harmony cfDNA test can be performed from 10 weeks of pregnancy, two weeks earlier than the NHS 11-14 week screening. The Harmony test has a greater sensitivity, specificity and higher positive predictive value (PPV) than the Nuchal Translucency screening, also known as the Combined Test.

How reliable are Harmony tests?

How accurate is The Harmony test? The Harmony test detects 99% of babies with Down and Edwards syndrome. For Patau’s syndrome it will detect 92-99% of babies, depending on the test you choose.

Can NIPT test Miss Down syndrome?

NIPT is quite accurate for Down syndrome (99%) and for trisomy 18 (97%). It is less accurate for trisomy 13 (87%). In all cases, the results should not be considered certain unless confirmed by diagnostic testing. Two diagnostic procedures can usually confirm or disprove the results of NIPT.

How are blood tests inconclusive?

An inconclusive result is neither positive nor negative. This result can occur from inadequate sample collection, very early-stage infection, or for patients close to recovery. With an inconclusive result, collecting and testing another sample is recommended.