Why and When Is the Triple or Integrated Screening Test Performed?

Reviewed by: Dr. Ashan

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5 min read

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Apr 16, 2025

Early and accurate evaluation of foetal health is absolutely vital during pregnancy to direct clinical treatment and assist in parent decision-making. Prenatal screening is one of the main non-invasive instruments used for this aim since it evaluates the risk of several chromosomal abnormalities and neural tube problems in the foetus. Usually offered during the second trimester among these are the triple test and integrated screening.

What Is the Triple Test?

A mother's triple screening test is a blood test designed to gauge three particular substances levels within her body:

  1. Alpha-fetoprotein (AFP): A protein produced by the fetal liver.
  2. Human chorionic gonadotropin (hCG): A hormone produced by the placenta.
  3. Unconjugated estriol (uE3): An estrogen produced by both the fetus and placenta.

Sometimes, a fourth marker, inhibin A, is added—making it a quadruple screen—but the principle remains the same.

The triple test estimates the risk (not a diagnosis) of:

  • Down syndrome (Trisomy 21)
  • Edwards syndrome (Trisomy 18)
  • Neural tube defects (e.g., spina bifida and anencephaly)

What Is the Integrated Screening Test?

Integrated screening combines second trimester triple test findings with information from first-trimester screening (including serum indicators like PAPP-A) and nuchal translucency ultrasonic findings. Particularly with Down syndrome, the combined method raises the sensitivity and specificity of spotting chromosomal abnormalities.

When Is the Triple or Integrated Screening Performed?

  • Triple test: Performed between 15 and 20 weeks of gestation, ideally between 16 and 18 weeks for the most accurate results.
  • Integrated screening: Begins in the first trimester (around 11–13 weeks) with the nuchal translucency scan and PAPP-A measurement, and concludes with the triple test in the second trimester.

The timing is important because biochemical markers fluctuate with gestational age. Accurate dating via an early ultrasound increases the reliability of the results.

Why Is This Screening Important?

The primary objective is early risk assessment. Although the test does not provide a definitive diagnosis, it helps:

  • Identify pregnancies that may benefit from further diagnostic testing (such as amniocentesis or chorionic villus sampling).
  • Offer reassurance in low-risk cases.
  • Guide counseling and planning for parents who may be at increased risk.

Early detection of anomalies will enable healthcare professionals to guarantee prompt referrals to experts, offer suitable genetic counselling, and assist families in making wise decisions on continuing pregnancy treatment.

Conclusion

The triple or integrated screening test is a valuable component of prenatal care, performed between 15 and 20 weeks of pregnancy, with integrated screening starting as early as 11 weeks. These tests help evaluate the likelihood of certain fetal conditions, allowing for early intervention and support when needed. While not diagnostic, they serve as a first step in a continuum of care aimed at ensuring the best outcomes for both mother and baby.

References:

  1. Reynolds, T. (2010). The triple test as a screening technique for Down syndrome: reliability and relevance. International Journal of Women S Health, 83–83. https://doi.org/10.2147/ijwh.s8548
  2. ‌Wald, N. J., Watt, H. C., & Hackshaw, A. K. (1999). Integrated Screening for Down’s Syndrome Based on Tests Performed during the First and Second Trimesters. New England Journal of Medicine, 341(7), 461–467. https://doi.org/10.1056/nejm199908123410701
  3. ‌Reynolds, T. (2010). The triple test as a screening technique for Down syndrome: reliability and relevance. International Journal of Women S Health, 83–83. https://doi.org/10.2147/ijwh.s8548
  4. ‌Gordon, S., Umandap, C., & Langaker, M. D. (2023, January 16). Prenatal Genetic Screening. Nih.gov; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK557702/