Information
The triple test is one of the methods used to detect congenital developmental abnormalities in the foetus. It involves measuring the concentration of three biochemical markers in a blood sample taken from the expectant mother. The triple test played a significant role in earlier decades, before the introduction of first-trimester combined screening, when it was the primary method for detecting foetal abnormalities. Today's combined screening is a sufficiently reliable method that allows potential foetal abnormalities to be identified as early as the first trimester of pregnancy. The role of the triple test is therefore now largely supplementary.
How it works
The test is performed by analysing a blood sample taken at week 16 of pregnancy. The three biochemical markers measured are alpha-fetoprotein (AFP), total human chorionic gonadotropin (hCG), and unconjugated oestriol (uE3). The test is used to screen for certain foetal abnormalities, including neural tube defects and Down syndrome.
When it is used
Compared to the first-trimester combined screening currently in use, the triple test has several limitations: it cannot be performed before week 15 of pregnancy, has a detection rate of approximately 70%, and carries a relatively high rate of false positives. The triple test can still be valuable today as part of an integrated testing approach, where its results are combined with ultrasound findings and first-trimester biochemical markers to achieve the most accurate screening parameters possible. The triple test also remains a useful screening option for clients who present to their doctor at a later stage of pregnancy and have not undergone first-trimester screening.
