What Is the Panorama Prenatal Test and How Does It Work?

The Panorama prenatal test is a brand-name noninvasive prenatal screening test (often called NIPT or NIPS) that analyzes fragments of DNA circulating in a pregnant person’s blood to estimate the chance that a fetus has certain chromosome conditions, including Down syndrome. What sets Panorama apart from most other NIPT options is its technology: rather than counting all DNA fragments across the genome, it zeroes in on thousands of specific single-nucleotide polymorphisms (SNPs) scattered across the chromosomes of interest, then uses a statistical model to tease apart which DNA came from the pregnancy and which came from the parent. That distinction matters more than it might sound, because it shapes what the test can and cannot detect, how it handles edge cases like twins, and why its failure modes differ from other screens.

Where the DNA Comes From

A common misconception is that NIPT reads fetal DNA directly. It does not. The DNA fragments floating in maternal blood actually originate from the placenta, not the fetus itself. More specifically, the outer layer of the placental villi, called the syncytiotrophoblast, continuously sheds small fragments of DNA into the parent’s circulation as its cells undergo normal turnover and programmed cell death.¹ Because the placenta is genetically almost identical to the fetus in most pregnancies, reading placental DNA is a reliable stand-in for reading fetal DNA. But the word “almost” carries weight: the placenta and fetus occasionally differ, and that gap is one of the main reasons NIPT can sometimes give a wrong answer.

These cell-free DNA (cfDNA) fragments are short, and they mix in with the parent’s own cfDNA. The proportion that comes from the pregnancy is called the fetal fraction. In a typical first-trimester sample, fetal fraction is somewhere around 10 to 15 percent. Panorama requires a minimum fetal fraction to return a result, generally around 2.8 to 3 percent. Below that threshold, the signal from the pregnancy is too faint for the algorithm to distinguish reliably from background noise, and the lab will report a test failure rather than guess.

How the SNP Approach Differs From Counting Methods

Most NIPT platforms on the market use a method called whole-genome sequencing, or WGS. In simplified terms, they sequence millions of cfDNA fragments, map them to the genome, and check whether any chromosome shows up more often than expected. If chromosome 21 fragments are overrepresented, it raises the suspicion of trisomy 21. The approach is straightforward but treats all cfDNA as one pool and does not try to separate the parent’s DNA from the pregnancy’s DNA.

Panorama takes a different route. It targets roughly 13,000 SNP sites across the chromosomes it screens. At each site, the algorithm compares the expected pattern of genetic variants with the actual sequencing data, factoring in parental genotype information, crossover frequencies, and linkage patterns to predict what the sequencing data should look like for every plausible combination of fetal genotype and fetal fraction. It then identifies the combination that best matches the observed data.² This is sometimes called the NATUS algorithm. Because it models the fetal and maternal contributions separately, it can estimate the fetal fraction directly and even determine whether the extra chromosome in a trisomy came from the egg or the sperm.

The tradeoff is that the SNP method is more sensitive to low fetal fractions. Research comparing the two approaches found that the SNP method cannot maintain acceptable performance below roughly 3 percent fetal fraction, whereas WGS-based methods retain high specificity even at low fractions and still achieve above 80 percent sensitivity for trisomies in those low-fraction samples.³ Panorama compensates by flagging low-fraction samples as no-calls rather than pushing through a potentially unreliable result, which is arguably a safer approach for the patient but does mean a higher chance of needing a redraw.

What Panorama Screens For

The standard Panorama panel covers the three most common autosomal trisomies: trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). It also screens for triploidy, sex chromosome conditions, and, if selected, certain microdeletion syndromes. That last category is where it pushes beyond what many other NIPT platforms offer.

For the common trisomies, Panorama’s detection rates are high. A large Swiss audit of more than 7,500 Panorama tests found sensitivity around 99.9 percent for each of the three trisomies, with false-positive rates of 0.10 percent for trisomy 21, 0.02 percent for trisomy 18, and 0.06 percent for trisomy 13.⁴ Pooled data from clinical performance studies using the same underlying methodology across more than 23,000 pregnancies showed sensitivity above 99 percent for trisomy 21, about 97 percent for trisomy 18, and around 94 percent for trisomy 13, with specificity above 99.9 percent for each.⁵

Sex Chromosome Screening Is Less Reliable

When Panorama or any NIPT platform moves beyond the common trisomies to screen for sex chromosome aneuploidies, such as Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X (47,XXX), or 47,XYY, the accuracy drops. This is not unique to Panorama; it is a limitation of cfDNA screening across the board. A systematic review and meta-analysis found that detection rates for Turner syndrome ranged from roughly 84 to 94 percent depending on the sequencing method, with targeted approaches performing somewhat less well, and specificity around 99.8 to 99.9 percent.⁶ For other sex chromosome conditions, sensitivities were at least about 76 percent, but the numbers are based on relatively few affected pregnancies.

Turner syndrome is the hardest to detect because it involves a missing X chromosome, and mosaicism is common. Many pregnancies with a Turner syndrome result on NIPT turn out to be false positives. One large Chinese study found that only 9 of 12 cases flagged as monosomy X by NIPT were confirmed, and mosaic cases were especially likely to be missed entirely.⁷ A retrospective review of NIPT-tested cases similarly found that mosaic Turner syndrome cases went undetected, consistent with the broader literature showing that detection rates and positive predictive values for sex chromosome conditions lag behind those for autosomal trisomies.⁸ Major professional bodies still recommend offering sex chromosome screening after counseling, but patients should understand that a high-risk result here is less predictive than one for trisomy 21.⁹

Microdeletion Screening and the 22q11.2 Example

Panorama is one of the few NIPT platforms that offers optional screening for microdeletion syndromes, the most prominent being 22q11.2 deletion syndrome (also known as DiGeorge syndrome or velocardiofacial syndrome). This condition, caused by a small missing segment on chromosome 22, affects roughly 1 in 1,000 to 1 in 4,000 live births and can cause heart defects, immune problems, and learning differences. Because it does not track with parental age the way trisomy 21 does, traditional screening approaches miss it entirely.

In a validation study using SNP-based NIPT, the test identified 9 out of 10 affected samples for a sensitivity of 90 percent and a specificity of about 99.7 percent.¹⁰ A larger clinical study found a somewhat lower sensitivity of 75 percent (9 of 12 cases detected), with a positive predictive value of only about 24 percent, meaning roughly three out of four high-risk results were false alarms.¹¹ That low positive predictive value is partly a consequence of the condition’s rarity: even a highly specific test will produce many false positives relative to true positives when the thing it is looking for is uncommon.

Efforts to improve this are ongoing. A recent study demonstrated that determining whether the deletion originated from the fetus or the parent could push the positive predictive value from 87 percent up to 94 percent in their cohort.¹² Still, microdeletion screening is the area where NIPT’s limitations are most visible. Professional societies have been more cautious in recommending routine microdeletion screening compared to trisomy screening, and any high-risk microdeletion result absolutely needs confirmatory diagnostic testing.

Triploidy and Vanishing Twins

One unusual capability of Panorama is its ability to flag triploidy, a condition in which the fetus has a complete extra set of chromosomes (69 total instead of 46). WGS-based NIPT methods struggle with triploidy because counting-based approaches are not well suited to detecting a proportional increase across every chromosome. The SNP approach can pick up triploidy because the extra set of chromosomes produces an identifiable pattern of additional alleles at each SNP site.¹³

An analysis of roughly 31,000 Panorama cases found additional fetal haplotypes, suggestive of triploidy or a hidden twin pregnancy, in about 0.4 percent of samples. Among those with clinical follow-up, about 5 percent turned out to be true triploid pregnancies, while the rest were mostly vanishing twins or unrecognized viable twin pregnancies.¹⁴ Triploidy is rare but clinically serious, often associated with molar pregnancies or early pregnancy loss, so the ability to flag it is a genuine advantage of the SNP platform.

Twin Pregnancies and Zygosity

Screening twins with NIPT adds complexity. In a dizygotic (fraternal) twin pregnancy, each fetus contributes its own cfDNA to the parent’s blood, and the two contributions may not be equal. If one twin has a low fetal fraction, a positive result could be masked or a negative result could be falsely reassuring. Panorama’s SNP-based method can measure individual fetal fractions for each twin in dizygotic pregnancies and can also determine zygosity, distinguishing whether the twins are identical or fraternal.¹⁵ That ability to assign individual fractions is not something WGS-based tests can easily do, since they treat all fetal cfDNA as one pool.

Knowing zygosity early can be clinically useful. It can help clarify chorionicity when that was not reliably determined on ultrasound, and it helps clinicians assess whether one or both fetuses might be affected by a flagged condition.¹⁶ Major guidelines now recommend NIPT as a screening option for twin pregnancies, not just singletons.¹⁷

Why Fetal Fraction Matters and What Can Lower It

A low fetal fraction is one of the most common reasons for a Panorama test to come back without a result. Higher maternal weight is the strongest predictor. A study controlling for other variables found a consistent negative relationship between body mass index and fetal fraction, with obese women having significantly lower fractions throughout the first trimester compared to women of normal weight.¹⁸ The issue is not that obese women produce less placental DNA; rather, they produce more of their own cfDNA, which dilutes the fetal signal. One study found that low fetal fraction (below 4 percent) occurred in about 4.5 percent of normal-weight women but in roughly 20 percent of obese women, rising to about 36 percent in women with severe obesity.¹⁹

But low fetal fraction is not just a nuisance. A meta-analysis found that when samples fail due to low fetal fraction, the pregnancies behind those failures carry elevated odds of certain chromosome problems, including trisomy 13, trisomy 18, monosomy X, and especially triploidy, compared to pregnancies with normal fetal fraction.²⁰ A separate large study found that NIPT failures due to low fetal fraction were also associated with rare chromosomal abnormalities at significantly increased odds, along with conditions like antiphospholipid syndrome and the use of low-molecular-weight heparin.²¹ For this reason, a no-result is not reassuring. Providers generally recommend a repeat draw or, in some cases, moving directly to diagnostic testing after a failed NIPT.

Why a Positive Result Does Not Mean a Diagnosis

This is probably the single most important thing to understand about Panorama or any NIPT: it is a screening test, not a diagnostic test. A high-risk result raises the probability of a condition but does not confirm it. The gap between a positive screen and a confirmed diagnosis is measured by the positive predictive value (PPV), which depends heavily on how likely the condition was in the first place.

When researchers stratified NIPT-positive cases by pre-existing risk level, the differences were stark. Among women in a high-risk category, such as those over 35 or those with abnormal ultrasound or prior affected pregnancies, the PPV reached about 54 to 88 percent depending on the specific risk factors. Among low-risk women, the PPV dropped to around 32 percent, meaning roughly two-thirds of positive results were false alarms.²² Maternal age alone made a measurable difference: PPV was about 65 percent in women 35 and older versus about 46 percent in younger women in the same study.

The main source of false positives is confined placental mosaicism, a situation where the placenta carries a chromosomal anomaly that the fetus does not share.²³ Because NIPT reads placental DNA, it reports what the placenta’s chromosomes look like, and sometimes the placenta diverges. This is also why confirmatory testing after a high-risk result is essential. That confirmation typically involves amniocentesis or chorionic villus sampling (CVS). A recent study found that CVS provided a definitive diagnosis in about 97.5 percent of high-risk NIPT results for trisomy 21 and 100 percent for trisomy 18, though only about 87 percent for trisomy 13, where placental mosaicism is more common.²⁴

Common Misunderstandings About Negative Results

A low-risk (negative) result on Panorama means the test found no evidence of the screened conditions. It does not guarantee a healthy baby. This sounds obvious in print, but research shows many patients walk away believing it does. A study assessing patient understanding found that participants scored lowest on questions about whether a negative NIPT result ensures a healthy baby or eliminates the possibility of Down syndrome. Most patients were satisfied with their understanding of NIPT, yet a substantial number did not fully appreciate the test’s limitations.²⁵

A negative result means the conditions Panorama screens for are unlikely. It says nothing about the hundreds of other genetic conditions the test does not cover, structural birth defects, or non-genetic complications. This is why standard prenatal care, including anatomy ultrasounds and other routine evaluations, remains important regardless of NIPT results.

Impact on Amniocentesis and CVS Rates

Before NIPT became available, the main pathway for prenatal chromosome screening involved serum markers and nuchal translucency ultrasound, with invasive testing offered to those who screened positive or were considered high-risk by age. Those invasive procedures, amniocentesis and CVS, carry a small but real risk of pregnancy loss. The introduction of NIPT as an intermediate screening step has substantially reduced the number of women who go on to invasive testing.

At one center, the rate of amniocentesis dropped from about 8 percent to about 5 percent after NIPT became available, and overall invasive procedures fell from roughly 12 percent to about 9 percent of pregnancies.²⁶ In Australia, a national-level analysis found that the introduction of cfDNA testing was associated with the steepest decline in amniocentesis and CVS procedures in two decades.²⁷ A cost-effectiveness analysis in Brazil’s private health system estimated that NIPT implementation reduced amniocentesis procedures by about 18 percent and lowered procedure-related pregnancy losses.²⁸ The reduction in unnecessary invasive procedures is one of the clearest practical benefits of NIPT in general and applies to Panorama alongside other platforms.

Incidental Findings That Have Nothing to Do With the Fetus

Because NIPT reads all cfDNA in the blood, not just placental DNA, it occasionally stumbles onto something unexpected in the parent’s own genome. The most attention-grabbing example is occult maternal cancer. Tumors shed DNA into the bloodstream just as the placenta does, and those tumor-derived fragments can create patterns that look like multiple chromosomal abnormalities on NIPT, a result that does not match any single fetal condition.

A large screening study of nearly two million pregnant women found that when NIPT flagged multiple chromosomal aneuploidies simultaneously, about 8 percent of those cases turned out to involve a maternal malignancy. Using a specialized algorithm to analyze the pattern of chromosome-level abnormalities, researchers were able to identify roughly 83 percent of the confirmed cancers while excluding most false positives.²⁹ This is not something Panorama is marketed for, and it is not the reason anyone orders the test, but it has emerged as an occasional and clinically significant byproduct of cfDNA screening.

When Panorama Is Typically Offered

Panorama can be performed as early as nine weeks of gestation. Most providers order it between weeks 10 and 13 of pregnancy, which is when fetal fraction has risen enough to give reliable results in the majority of patients. The American College of Medical Genetics and Genomics (ACMG) recommends cfDNA-based screening over traditional serum screening for all pregnant patients with singleton pregnancies, not just those considered high-risk, for trisomies 21, 18, and 13.¹⁷ Insurance coverage varies. Some plans cover NIPT for all pregnancies, some only for those classified as high-risk, and out-of-pocket costs can range widely depending on the carrier and region.

For patients who receive a high-risk result, the next step is always a conversation with a genetic counselor or maternal-fetal medicine specialist and, if desired, confirmatory diagnostic testing. For patients who receive a low-risk result, standard prenatal care continues as usual. And for the patients who get no result at all due to low fetal fraction, the conversation is more nuanced: a redraw may work, but the possibility that the failed test itself carries clinical significance deserves discussion.