A NIPT result is typically a one-page or two-page report that lists each condition screened and assigns a risk level, most commonly “low risk” or “high risk,” for each one. You’ll also see your baby’s predicted sex (if you opted in) and a number called the fetal fraction. Results usually arrive within 5 to 7 days after your blood is drawn.
If you’re waiting on results or just got them back, here’s a breakdown of every section you’ll see on the report and what each piece means.
How Risk Levels Are Reported
The core of your NIPT report is a list of chromosomal conditions, each followed by a risk classification. Most labs use the terms “low risk” and “high risk,” though some use “low chance” and “high chance” instead. You won’t typically see the words “positive” or “negative,” and you shouldn’t see “normal” or “abnormal.” The field has moved away from those terms because NIPT is a screening test, not a diagnosis.
A typical result looks something like this:
- Trisomy 21 (Down syndrome): Low risk
- Trisomy 18 (Edwards syndrome): Low risk
- Trisomy 13 (Patau syndrome): Low risk
Each condition gets its own line. A low-risk result across all three is the most common outcome and means the test found no signs of extra chromosomal material for those conditions. A high-risk result on any line means the test detected a pattern suggesting an extra chromosome, but it does not confirm the condition exists. It means further testing is recommended.
What Conditions the Report Covers
Every NIPT report screens for the three most common autosomal trisomies: trisomy 21 (Down syndrome), trisomy 18 (Edwards syndrome), and trisomy 13 (Patau syndrome). These are the conditions the test performs best at detecting.
Many labs also screen for sex chromosome differences. These include Turner syndrome (a missing X chromosome), Klinefelter syndrome (XXY), triple X syndrome (XXX), and XYY syndrome. Sex chromosome results may appear on a separate section of the report or be included alongside the trisomy results. Some labs only include this panel if you or your provider specifically requested it, so if you don’t see it, that may be why.
Expanded panels from certain labs go further, screening for smaller chromosomal deletions like DiGeorge syndrome. These expanded results appear in their own section and tend to have lower accuracy than the core trisomy screening.
Fetal Sex on the Report
If you chose to learn the baby’s sex, the report will state it simply: “male” or “female.” Some labs phrase it in terms of chromosomes detected, such as “XY” or “XX.” The test determines this by looking for the presence or absence of Y-chromosome DNA in your blood sample. This is one of the most reliable parts of the entire test, though rare discrepancies with ultrasound findings can occur in certain genetic conditions.
If you asked your provider not to reveal the sex, this section is either omitted or sealed separately so the rest of your results can be shared without it.
What the Fetal Fraction Number Means
Somewhere on your report, you’ll see a percentage labeled “fetal fraction.” This tells you how much of the free-floating DNA in your blood sample actually came from the placenta (which represents the baby) versus from you. A typical fetal fraction might read anywhere from about 4% to 20% or higher.
This number matters because the test needs enough placental DNA to produce a reliable reading. Most labs require a fetal fraction between 2% and 4% at minimum. If yours was, say, 12%, the lab had plenty of material to work with. If it fell below the lab’s threshold, the test may not return a result at all.
When Results Come Back Inconclusive
About 1 to 3% of NIPT samples don’t produce a clear answer. Your report might say “no result,” “no call,” or “inconclusive” for one or more conditions. This does not mean something is wrong with your baby. The most common reason is a fetal fraction that was too low for the lab’s technology to analyze confidently.
Several factors can contribute to a low fetal fraction. Higher maternal BMI is one of the most common, since more maternal DNA in the bloodstream dilutes the placental signal. Testing very early in pregnancy (before 10 weeks) can also produce low fetal fractions because the placenta hasn’t released enough DNA yet. Twin pregnancies, particularly with non-identical twins, have higher failure rates, around 5.6% compared to about 1.7% for singletons in one large dataset.
If you get an inconclusive result, your provider will typically offer a redraw, often a couple of weeks later to give the fetal fraction time to rise. In some cases, you may be offered diagnostic testing instead.
How Accurate a High-Risk Result Really Is
This is one of the most important things to understand about your report. A “high risk” result does not mean your baby definitely has that condition. The chance that a high-risk result is correct varies significantly depending on the condition and your age.
For trisomy 21, the positive predictive value (the chance a high-risk flag is a true positive) is roughly 86% in studies of mixed-age populations. That means about 14 out of 100 people flagged high-risk for Down syndrome will find out after diagnostic testing that the result was a false alarm. For trisomy 18, that accuracy drops to about 58%, and for trisomy 13 it falls to around 25%, meaning three out of four high-risk results for trisomy 13 turn out to be false positives.
Your age affects these numbers substantially. In one large study, the overall positive predictive value for women 35 and older was about 65%, compared to roughly 46% for women under 35. When multiple risk factors were present (such as advanced maternal age plus abnormal ultrasound findings), the positive predictive value climbed above 97%. The takeaway: a high-risk NIPT result is a reason for further testing, not a final answer.
What Happens After a High-Risk Result
If any line on your report reads “high risk,” the next step is diagnostic testing to confirm or rule out the condition. The two options are chorionic villus sampling (CVS), which can be done earlier in pregnancy, and amniocentesis, which is typically performed after 15 weeks. Both involve collecting a small sample of cells that carry the baby’s actual genetic material, giving a definitive yes or no.
Your provider will likely recommend a detailed ultrasound with a fetal medicine specialist as well. If that scan shows structural differences consistent with the flagged condition, either CVS or amniocentesis can be offered based on how far along you are and your preference. If the ultrasound looks completely normal, amniocentesis tends to be the preferred option because it analyzes fetal DNA directly rather than placental tissue, avoiding a phenomenon called confined placental mosaicism, where the placenta’s chromosomes differ from the baby’s. Amniocentesis results typically come back within 2 to 3 days.
Reading a Low-Risk Report
A fully low-risk report is straightforward: each condition listed shows “low risk,” the fetal fraction met the lab’s threshold, and if you opted in, the fetal sex is stated. No follow-up genetic testing is needed based on these results alone. Your regular prenatal care continues on its usual schedule, including the anatomy scan around 18 to 20 weeks, which looks at structural development rather than chromosomes.
Keep in mind that “low risk” is not the same as “no risk.” NIPT catches the vast majority of trisomy 21 cases (over 99% in most validation studies), but no screening test is perfect. A small number of affected pregnancies will receive a low-risk result. For most people, though, a low-risk NIPT provides strong reassurance.