What will the test tell me?
Quadruple test
A triple test is a blood test that is slightly more involved than an
AFP test. In addition to measuring the alpha-fetoprotein (AFP) for neural tube defects, it also measures 2 other hormones called 'unconjugated oestriol' and 'human chorionic gonadotrophin' (or HCG). These 2 hormone levels are combined with the woman's age to calculate a 'risk figure', or the chances of the baby having Down Syndrome (also called 'trisomy 21').
People with Down syndrome have an extra chromosome. This can make the person have specific physical features and various levels of intellectual disability and possibly other physical problems. However, many people with Down syndrome lead active and full lives in semi-dependent manner. Other names for the triple test include 'The maternal serum test', the 'Bart's test' or 'biochemical testing'.
What will the test tell me?
A triple test is done by taking a blood sample at 16 weeks of pregnancy (but it can be taken between 14 and 21 weeks). The 3 test results are combined with the woman's age and expressed as either 'low' or 'screen negative', meaning the baby is probably not affected, or 'screen positive' or 'high' if the baby is thought to be at risk of having a disorder. Alternatively, you may be given a specific figure expressed as an 'odd'. A 'low risk' is usually more than 1:300 (for example, 1:400) and a 'high risk' is less than 1:300 (for example, 1:30). These estimates are explained fully in class B,
understanding 'the numbers'.
NOTE:As a guide, a 'high' AFP level may indicate a baby with a neural tube defect and an abnormally 'low' AFP level, 'low' unconjugated oestriol and 'high' human chorionic gonadotrophin may indicate a baby with Down syndrome.
The triple test is a 'screening test'.