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Medical Advertisement Ministry of Health License No. FJSRS3IN-090623 – valid upto 15.06.2024

First & Second Trimester Risk Calculation

First & Second Trimester Risk Calculation


First Trimester Risk Calculation (WOG 11+0 – 13+6). For sample report, please click here.
Second Trimester Risk Calculation (WOG 14+0 – 18+6) also available.


Freiburg Medical Laboratory offers the First Trimester Screening (FTS) as a non-invasive pregnancy evaluation, performed at 11+0 – 13+6 week. The screening involves a combination of ultrasonographic measurement of nuchal translucency (NT) and biochemical analysis of maternal serum levels of two pregnancy-related proteins: free beta-hCG (beta-human chorionic gonadotropin) and PAPP-A (Pregnancy Associated Plasma Protein-A). Please note that numerous studies have revealed that the first trimester screening is far more sensitive for detecting Down syndrome than the second trimester screening (Triple test).


By combining the results of the ultrasound and blood test along with the age, ethnic origin and weight of the mother, a statistical evaluation of the biochemical parameters gives the NT-adjusted risk calculation which allows an early recognition of approx. 90% of Down syndrome cases as well as trisomies 13 + 18 at a false-positive rate of approx. 5%. A calculation is possible starting with week of gestation 11 + 0 and a crown-rump length (CRL) of 40-84 mm.

Required Patient Data

DOB mother, CRL (crown rump length), NT, weight of mother, date of withdrawal, date of ultrasound, smoker status, ethnic origin


Serum from the same day of NT measurement

Pre Analytics

Sample must be cooled or frozen, no whole blood! Heating up or long transportation times will cause false values of free ß-HCG


Electrochemiluminescence Immunoassay (ECLIA)


In our results, we indicate the adjusted (combined) risk for trisomy 21 apart from the risk based on the mother’s age. For a risk greater than 1:150 further, clarification is recommended. Similarly, a negative result does not completely rule out these abnormalities but instead decreases the specific risks for Down syndrome and trisomies 13 + 18.

Turnaround time

2-3 days

Accredited according to DIN EN ISO 15189

Lab hours

MON - THU and SAT 9:00 AM to 9:00 PM | FRI and SUN : 9:00 AM to 6:00 PM

Key Technical Personnel