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What is Enhanced FTS?
Enhanced FTS is a new first trimester screening test that uses 4 serum markers plus the nuchal translucency (NT) measurement, along with maternal age to generate a pregnancy specific risk for Down syndrome. The two new markers that are analyzed include placental growth factor (PlGF) and first trimester alpha fetoprotein (AFP). This is in addition to PAPP-A and beta hCG, which have always been part of the FTS.
What does it screen for?
Enhanced FTS is a screening test for Down syndrome. It can also indicate when there is a high risk for Trisomy 18.
What does it not screen for?
Enhanced FTS does not screen for open neural tube defects (ONTD) or spina bifida. It does not screen for all chromosome problems in pregnancies. At this time, it is not a screening test for adverse obstetrical outcomes or pre-eclampsia, however individual practitioners may use the information from this test to identify high risk patients.
What is the recommended screen for spina bifida/ONTD?
The Society of Obstetrics & Gynecology guidelines regarding screening for fetal neural tube defects endorses the use of ultrasound (18-20 weeks) for screening of ONTD (October 2014).*
Is enhanced FTS a good test?
By including the two new markers, enhanced FTS is an improvement over FTS. It has been shown to have a detection rate that is comparable to integrated prenatal screen (IPS). We estimate a detection rate of 85-90%. See tables below.
Why should I order this test for my patient?
Enhanced FTS will allow your patients to have information about their pregnancy in the first or early second trimester. For those who have a positive screen result, they can access Non-Invasive Prenatal Testing (NIPT) or diagnostic testing sooner than if they had IPS.
How do I order enhanced FTS?
The Trillium Health Partners (THP) Prenatal Screening Requisition has been updated and can be accessed from our website at http://trilliumhealthpartners.ca/patientservices/genetics/Pages/requisitions-forms.aspx
When can I start ordering enhanced FTS?
On April 3, 2017 all samples received by THP that are accompanied with a request for FTS will be reported as an enhanced FTS. After this date, the previous two marker-FTS will no longer be performed.
*”The primary use of MS-AFP for the screening of open/closes neural tube defects screening should be discontinued with the limited clinical exceptions of pregnant women with a BMI >35 kg/m2 or when geographical or clinical access factors limit timely and good quality ultrasound screening at 18-22 weeks”
Screening Test |
Detection Rate |
False Positive Rate |
Current FTS |
78-85% |
8-9% |
Enhanced FTS (eFTS) |
85-90% |
3-6% |
eFTS (no NT ) |
~80% |
~5% |
IPS |
85-90% |
2-4% |
MSS (quad screen) |
75-85% |
5-10% |
Table 1: Comparison of Prenatal Screening Options
