The triple test assesses the risk of having a Down's baby based on:
- maternal serum markers - alpha feta protein, unconjugated
oestriol and total human chorionic gonadotrophin.
Serum is taken from 15-20 weeks gestation, ideally 16 weeks. A high hCG, low
AFP and low oestriol suggest a Down's child. Results are expressed in terms
of the risk of having a Down's child eg. 1 / 145. Detection rates range from
45-65% with a 5% false positive rate. Those with a risk greater than 1 in 200
are offered amniocentesis.
Other risks may also be detected eg. a high AFP suggests a neural tube defect.
Improved combined methods of screening are now available and women should
not be offered the triple test in the UK.
Note that the triple test was known as the Barts test in some areas.
The recommended method of screening for Down's syndrome is using the Combined
Test. Combined screening can be carried out in the first trimester and up to
14 weeks and 1 day of pregnancy.
Women who present too late for combined screening should be offered quadruple
testing in the second trimester of pregnancy.
For more information: NHS Fetal Anomaly Screening Programme (NHS FASP) www.fetalanomaly.screening.nhs.uk
- 1. NICE. Antenatal care: routine care for the healthy pregnant woman. England:
NHS National Institute for Health and Clinical Excellence; 2008 Mar. Report
No.: Clinical guidelines CG62.
- 2. NHS Fetal Anomaly Screening Programme. Antenatal screening - working
standards for Down's syndrome screening 2007. NHS FASP; 2007.
- 3. NHS Fetal Anomaly Screening Programme. Consent standards for screening
fetal anomalies during pregnancy 2007. NHS FASP; 2007.
- 4. NHS Fetal Anomaly Screening Programme. Screening for Down's syndrome:
UK NSC Policy recommendations 2011-2014 Model of Best Practice. Department
of Health; 2011.
- 5. Kirwan D, NHS FASP. 18+0 to 20+6 weeks fetal anomaly scan -National
standards and guidance for England 2010. Exeter, England: NHS Fetal Anomaly
Screening Programme; 2010.