Summary of this article
The Quattro test calculates a probability from four components in a blood sample. NIPT (Non-Invasive Prenatal Testing) directly analyzes fragments of the baby’s DNA circulating in the mother’s blood. The two tests differ in the number of conditions covered, accuracy, how results are reported, and the timing window in which you can be tested.
More pregnant women are choosing NIPT in recent years. That said, the Quattro test can still be the right choice if you don’t meet the eligibility conditions for NIPT, or if you want to keep costs down. This article lines up the differences in a comparison table and walks through the points to weigh when you’re not sure which to choose.
What this article covers
- How the Quattro test and NIPT work, and which conditions each one screens for
- A side-by-side table of the number of conditions covered, accuracy, how results are reported, and the testing window
- Why more pregnant women are moving from the Quattro test to NIPT
- How to choose between the two, and what happens next if a result comes back positive
What is the Quattro Test?
The Quattro test is a screening test that measures four components in a pregnant woman’s blood and uses them to calculate the probability of certain conditions. A screening test estimates a probability by identifying pregnancies at higher likelihood; it does not give a yes/no diagnosis. Japan’s Ministry of Health, Labour and Welfare describes this test as a “maternal serum marker test” in its glossary of maternal and child health terms.
What sets it apart is that it recalculates the age-based probability by factoring in the blood test values. Because it doesn’t rely on age alone, it gives a more precise probability than an age-only estimate.
Conditions the Quattro test can screen for
The Quattro test covers only three conditions. It calculates the probability that a baby has trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), or an open neural tube defect. Trisomy 13 and sex chromosome aneuploidies are not included.
Accuracy and how to read the results
The Quattro test is a non-diagnostic screening test. Past studies put the positive predictive value at around 87% for trisomy 21 and around 83% for open neural tube defects. For trisomy 18, it’s around 77%. It’s not a diagnostic test, but as a probability estimate it carries a reasonable level of reliability.
Results are reported as a probability, such as “1 in 100.” If the figure falls below a preset cutoff, the result is “negative”; if it’s above the cutoff, it’s “positive.” A negative result doesn’t bring the chance of the condition to zero, and a positive result doesn’t confirm it either. This non-diagnostic nature is something the Quattro test shares with NIPT, which we cover next.
Testing window and how the test is done
The recommended window is roughly week 15 through week 17 of pregnancy. You can still be tested up to around week 21, but leaving enough time to decide whether to proceed to amniocentesis afterward is worth keeping in mind, so testing by around week 17 is more comfortable. Note that you cannot be tested before 15 weeks.
The test itself only requires a blood draw. Levels of four components in the blood — AFP, hCG, uE3, and inhibin A — are measured and combined with maternal age and gestational week to calculate the probability.
The calculated probability tends to rise with maternal age. That’s not a sign of lower test accuracy; it simply reflects the established relationship between age and the underlying rate of chromosomal conditions.
We cover what happens after a positive Quattro test result later in this article, in the section on what to expect if a result comes back positive. For a general idea of costs, see our article on the cost of prenatal testing.
What is NIPT?
NIPT (Non-Invasive Prenatal Testing) is a screening test that directly analyzes fragments of the baby’s DNA circulating in the mother’s blood to check for chromosomal number abnormalities. Clinical use began in the United States in 2011, and the test spread in Japan from 2013 onward under the name “new prenatal testing.”
Today it can be performed from around 6 weeks of pregnancy. Unlike amniocentesis, it carries no miscarriage risk. That said, like the Quattro test, it is not a diagnostic test — a positive result still needs to be confirmed with a diagnostic test such as amniocentesis. Japan’s Children and Families Agency also emphasizes, in its maternal and child health policy, that prenatal testing should come with adequate information for pregnant women and respect for their own decisions.
What NIPT can tell you
The standard panel covers three conditions: trisomy 13 (Patau syndrome), trisomy 18 (Edwards syndrome), and trisomy 21 (Down syndrome). Some clinics extend the panel to sex chromosome aneuploidies and even whole-chromosome partial deletion and duplication conditions.
Interpreting the result isn’t always straightforward without specialized knowledge. If a result comes back positive, meeting with a specialist such as a genetic counselor to understand exactly what it means is an important step. Taking that extra step to confirm what the result actually means — rather than assuming “negative means all clear” — shapes the decisions that follow.
Facilities offering NIPT in Japan operate under the accreditation framework run by the Japan Association of Obstetricians and Gynecologists’ prenatal testing certification committee, which also requires that genetic counseling be available.
Points to know about the results
NIPT results are reported as “negative” or “positive.” Hiro Clinic NIPT offers it as a non-diagnostic test with detection sensitivity above 99.9% for the major conditions it covers, including trisomy 21. Even so, a definitive diagnosis can only come from amniocentesis.
- It’s worth understanding beforehand what a given result would actually mean for you.
- The probability of detecting trisomy 13, trisomy 18, and trisomy 21 varies with maternal age.
- The test can sometimes reveal the baby’s sex, though the prediction is very occasionally wrong.
- Not every chromosomal condition or congenital condition is covered by the test.
- The exact items reported and the wording used can differ between testing laboratories.
Talking to women who have actually gone through it, the anxiety of waiting for results comes up again and again. On X, @m0nica_chan, who had a Quattro test at a prenatal checkup, posted: “Got my Quattro test result today at my prenatal checkup — negative. Such a relief.”
Whether the result comes back as a number or as negative/positive, the feeling of waiting is much the same for the Quattro test and NIPT alike.
Quattro test vs. NIPT: a full comparison
Both the Quattro test and NIPT are non-diagnostic screening tests that only require a blood draw from the mother. Where they differ is the conditions covered, accuracy, how results are reported, the testing window, and cost. Start with the comparison table below for the big picture, then read on for the details.
| Comparison point | Quattro test | NIPT |
|---|---|---|
| How it’s done | Measures 4 blood components (AFP, hCG, uE3, inhibin A) | Analyzes fragments of the baby’s DNA in the mother’s blood |
| Conditions covered | 3 conditions (trisomy 21, trisomy 18, open neural tube defects) | 3 as standard; some facilities extend to all chromosomes and partial deletion/duplication conditions |
| How results are reported | A probability figure, such as “1 in 100” | “Negative” or “positive” |
| Testing window | Roughly weeks 15–17 (up to around week 21) | From around week 6 (after the heartbeat is confirmed) |
| Risk to the mother | Blood draw only, no added risk | Blood draw only, no added risk |
| Nature of accuracy | Age-based probability adjusted by blood values (positive predictive value roughly 77–87% depending on condition) | Direct DNA fragment analysis (detection sensitivity above 99.9% for the conditions covered) |
| Need for a diagnostic test | Amniocentesis or similar required if positive | Amniocentesis or similar required if positive |
| Cost | Generally lower than NIPT at most facilities | Varies by facility and by how many conditions are covered |
Difference in conditions covered and accuracy
NIPT has the edge when it comes to the breadth of conditions covered. The Quattro test is limited to three: trisomy 21, trisomy 18, and open neural tube defects. NIPT covers those same three as standard, and at some facilities can be extended to all chromosomes and to partial deletion/duplication conditions.
Accuracy differs too. Because the Quattro test works by adjusting an age-based probability with blood values, its positive predictive value stays in the roughly 77–87% range depending on the condition.
NIPT, as we also cover in our article comparing NIPT and amniocentesis for Down syndrome detection, is reported to have detection sensitivity above 99.9% for the conditions it covers. Both tests are still non-diagnostic screening tests, though — that part doesn’t change.
Difference in timing and eligibility
The testing window is also quite different. The Quattro test can’t be done before 15 weeks of pregnancy. NIPT, at some facilities, can be done from around 6 weeks, once the heartbeat is confirmed. For pregnant women who want results as early as possible, this gap is often the deciding factor.
Some facilities, including those certified under the Japan Medical Association’s framework, set age or other eligibility conditions for NIPT. The Quattro test, by contrast, has no special eligibility conditions as long as you’re within the 15–21 week window. This difference in eligibility is another factor that can steer which facility you choose.
Difference in cost
Cost varies so much by facility and by which conditions are covered that we can’t quote a single figure here. In general, the Quattro test tends to be the lower-cost option at most facilities. NIPT can also be kept more affordable by narrowing the panel of conditions tested. For current, exact pricing, check directly with the facility you’re considering.
Why more pregnant women are moving from the Quattro test to NIPT
In recent years, more pregnant women have been choosing NIPT over the Quattro test. One reason is NIPT’s higher detection accuracy for the conditions it covers. Another is the extra time it offers, since it can be done from an earlier point in pregnancy.
In our own clinic, we’re seeing this shift firsthand: “The Quattro test used to be the standard choice, but now more women are choosing NIPT.” This is especially true among women who had a Quattro test in a previous pregnancy and are now comparing the two options more deliberately for a second or third pregnancy.
Hearing from women who have experienced both tests is useful too. On X, @kumako3210 posted: “With my first child, I had both NIPT and the Quattro test — it gave me real peace of mind going into delivery.”
Having had that reassurance from both tests with an older child, it’s common for parents to reconsider what testing they actually need for a younger sibling’s pregnancy.
That said, a positive NIPT result still carries a small chance of being a false positive, and a diagnostic test is still needed to confirm it, just as with the Quattro test. On the other hand, a negative NIPT result comes with a negative predictive value of around 99.9% for the conditions it covers — high enough that it can be genuine reassurance and a reason to skip a diagnostic test that carries a miscarriage risk.
Not sure which to choose? Here’s how to decide
Whether the Quattro test or NIPT is the better fit depends on your gestational week, how broad a range of conditions you want covered, and your budget. Use the guide below to help narrow it down.
| If this describes you… | Consider this test |
|---|---|
| You want results as early as possible | NIPT (available from around week 6) |
| You want a basic screening test at a lower cost | Quattro test |
| You want broad coverage across many conditions | NIPT (at facilities covering all chromosomes and partial deletion/duplication conditions) |
| You don’t meet another clinic’s eligibility conditions for NIPT (such as age) | Quattro test, or an NIPT facility without those conditions |
Some women wonder whether it makes sense to have both. It’s not unusual to consider adding NIPT after already having a Quattro test, and just as common to weigh whether to move straight to amniocentesis after an NIPT result — there’s no single right pattern here.
Keeping in mind that both tests are non-diagnostic screening tests, the best approach is generally to decide together with your doctor.
In my own consultations, what I hear most often from women who are undecided is that they’re really asking, “What happens if it comes back positive?” The next section walks through exactly what that looks like.
If a result comes back positive: what happens next, and amniocentesis
Whether it’s the Quattro test or NIPT, a positive result means the next step is a diagnostic amniocentesis to confirm it. Amniocentesis involves inserting a fine needle through the abdomen to collect a small sample of amniotic fluid, which is then used to examine the baby’s chromosomes directly — this is what makes it a diagnostic, rather than screening, test.
For trisomy 21 or trisomy 18
Cells from the baby in the amniotic fluid sample are collected and examined for changes in chromosome number or structure. As the Japan Society of Obstetrics and Gynecology notes, amniocentesis does carry a small risk of miscarriage afterward. Talk it through carefully with your doctor before deciding.
For open neural tube defects
This is confirmed by measuring alpha-fetoprotein levels in the amniotic fluid, along with imaging such as ultrasound. An open neural tube defect occurs when the baby’s neural tube doesn’t form properly in early pregnancy, leading to abnormalities of the spinal cord or brain.
Many women worry about the cost of amniocentesis. Hiro Clinic NIPT offers subsidy plans that help cover the cost of amniocentesis. These also apply if you have the amniocentesis done at a different facility, so it’s worth checking the details in advance — it can take some of the weight off while you’re waiting for results.
NIPT at Hiro Clinic NIPT
At Hiro Clinic NIPT, there’s no age limit and no referral letter required, and you can be tested from as early as heartbeat confirmation. We’ve built a setup that’s easy to use whether you’ve already weighed the Quattro test against NIPT or are still deciding.
Beyond the standard trisomy 13, 18, and 21 panel, you can choose to extend testing to all chromosomes, including the sex chromosomes, and to partial deletion and duplication conditions across all autosomes. Testing is available for twin pregnancies as well. Because testing is carried out in partnership with a domestic testing institution (Tokyo Health Inspection Center), results are reported in as fast as 2 days, typically within about 5 days.
In case a result comes back positive, we also offer subsidy plans that help cover the cost of amniocentesis. The Light plan (JPY 3,300) covers up to JPY 100,000, the Standard plan (JPY 5,500) covers up to JPY 200,000, and the Wide plan (JPY 11,000) covers up to JPY 300,000.
These subsidies also apply if you have your amniocentesis at a facility other than Hiro Clinic. Board-certified obstetrician-gynecologists, pediatricians, and clinical genetics specialists work together, and genetic counseling is available as part of the process.
If you’re torn between the Quattro test and NIPT, start with a free consultation to get your questions answered. If anything here raises a question for you, please feel free to reach out.
FAQ: Quattro test vs. NIPT
Here are answers to the questions we hear most often, both at the clinic and on social media.
Q. Which is more accurate, the Quattro test or NIPT?
Comparing positive predictive value for the conditions covered, NIPT tends to be higher. The Quattro test’s positive predictive value runs around 77–87% depending on the condition, while NIPT is reported to have detection sensitivity above 99.9% for the conditions it covers. Neither, however, is a diagnostic test — both are non-diagnostic screening tests.
Q. Do I need to have both the Quattro test and NIPT?
No, it’s not required. Taking two screening tests that cover similar ground doesn’t get you any closer to a diagnosis on its own. If you’ve already had a Quattro test, talk with your doctor about whether to add NIPT or move straight to amniocentesis, based on your result and how far along you are.
Q. What should I do if my Quattro test comes back positive?
A positive result means “suspected,” not confirmed. In most cases, the next step is to talk with your doctor or a genetic counselor about whether to proceed to a diagnostic test such as amniocentesis. If you’re anxious, there’s no need to rush — talk to a specialist first.
Q. By when should I have NIPT done?
This varies by facility, but testing is generally available from around 6 weeks of pregnancy, once the heartbeat is confirmed. Most facilities recommend testing by roughly weeks 15–18. Since the Quattro test’s window runs from weeks 15–21, NIPT’s advantage is that you can get started much earlier.
Q. Which costs more, the Quattro test or NIPT?
The Quattro test tends to be the lower-cost option at most facilities. That said, cost depends heavily on how many conditions are covered, so check the exact figure with the facility you’re considering.
Q. Can I have the Quattro test or NIPT with a twin pregnancy?
Some facilities offer NIPT for twin pregnancies, including Hiro Clinic NIPT. The Quattro test’s calculation method tends to be less accurate for multiple pregnancies than for a single pregnancy, so NIPT is the more common choice for women expecting twins.
Medical supervision / author
Hiroshi Oka, M.D., Ph.D. — Director, Hiro Clinic (operated by Fukumikai Medical Corporation), and Labo Director. A graduate of Keio University School of Medicine, Dr. Oka passed the medical licensing exams in both Japan and the United States, and earned his Ph.D. in Medicine two years after completing clinical training. He is one of roughly 20 physicians in Japan to hold the Labo Director qualification. He also shares evidence-based information on pregnancy and prenatal testing through his YouTube channel, “Dr. Hiroshi’s Evidence-Based Pregnancy Channel.”
日本皮膚科学会 皮膚科専門医／日本医師会 産業医／東京衛生検査所 指導監督医
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