Second Trimester Screening (STS), also known as the double test, is a non-invasive maternal blood test performed between 14 weeks and 19 weeks 6 days of gestation. It measures two serum markers, Alpha-fetoprotein (AFP) and Total hCG, to estimate the risk of chromosomal conditions and neural tube defects (NTDs). STS can help identify pregnancies at increased risk for Trisomy 21 (Down syndrome), Trisomy 18/13, and NTDs such as spina bifida.
The detection rate of STS for Trisomy 21 is approximately 60–75%. STS is also valuable for detecting NTDs, making it an important option for women who miss early screening or present for care later in pregnancy.
| Specimen Requirements | |
|---|---|
| Clinical usage | Screens for Trisomy 21, Trisomy 18/13 (combined risk) & NTD (Neural Tube Defect) using 2 biomarkers (Total hCG & AFP). The specimen will be tested by our qualified referral lab |
| Type of sample | 5ml Blood (Plain Tube) |
| Patient requirement | Gestation Age: 14w0d -19w6d No fasting required Important information needed: – Date of birth, Ethnicity, Weight, Blood collection date, LMP & EDD – Smoker, yes/no – Number of fetus (singleton or twin) – Previous pregnancy history of T13, T18 or T21 – Assisted pregnancy details, (method, egg-freezing date, donor egg birth date, conception date & transfer date) if any – Biparietal diameter (BPD) NOTE: STS is only applicable for singleton and twin pregnancy |
| Storage & transportation | Store and transport in ROOM TEMPERATURE. If the sample cannot be transported to the laboratory on the same day of collection, please store it at 2°C to 8°C. |
| Turnaround Time (TAT) | 3 working days |
Allow us 2-3 days on weekends to tend to your enquiry.
Phone:
+603-7491 1700
Hotline:
+6019-600 2700
Fax:
+603-7499 3997
Our Services
Our Tests
Phone: +603-7491 1700
Hotline: +6019-600 2700
Fax: +603-7499 3997
Monday-Friday
8.30 am – 5.30 pm
Saturday
8.30 am – 1.00 pm