The triple Marker Screen test is also known as the triple test is a maternal blood screening test that looks for three specific substances: alpha-fetoprotein (AFP), human chorionic gonadotropin (HCG) and estriol. AFP is a protein that is produced by the fetus (embryo) and HCG is a hormone produced within the placenta. Estriol is an estrogen produced by both the fetus and the placenta. Moreover, the test is non- invasive performed through a blood test with little to no known risk to mother or developing a baby.
Importantly, the screening test does not diagnose a problem, they only signal that additional testing should be done.
When is the Triple Marker Screen Test performed?
The test is performed between 15th and 20th week of pregnancy however results received in the 16th – 18th week are considered to be more accurate. Every pregnant woman should be offered with a triple screen test, but it is recommended for women who:
- Have a family history of birth deficiencies
- Are 35 years or older
- Used possible harmful medications or drugs during pregnancy
- Have diabetes and use insulin
- Had a viral infection during pregnancy
- Have been exposed to high levels of radiation
How is the Triple Marker Screen Test administered?
The triple marker screen test is administrated in a hospital, clinic, doctor’s office, or lab. The process is similar to any other blood test. This involves drawing around 4- 5 ml of blood from mother which takes for 5- 10 minutes and will be sent to the laboratory for testing. The results usually take a few days after receiving the blood.
What does the Triple Marker Screen Test look for?
The triple screen measures high and low levels of AFP and abnormal levels of HCG and estriol. The results are combined with the mother’s age, weight, ethnicity, and gestation of pregnancy in order to assess the probabilities of potential genetic disorders.
AFP: High levels of this protein can indicate certain potential defects, such as neural tube defects like spina bifida or anencephaly.
HGC: Low levels may indicate potential problems with the pregnancy, including possible miscarriage or ectopic pregnancy. High levels of HGC can indicate a molar pregnancy or multiple pregnancies with two or more children.
Estriol: Low estriol levels may indicate the risk of having a baby with Down syndrome and Edward syndrome, especially when paired with low AFP levels and high HGC levels.
Down syndrome occurs when the fetus develops an extra copy of chromosome 21named as trisomy 21. It can cause medical problems and, in some cases, learning disabilities while Edward syndrome takes place when fetus develop an extra copy of chromosome 18 termed as trisomy 18can result in extensive medical complications. These are sometimes life-threatening in the first months and years after birth.
What are the results of the Triple Marker Screen Test?
It is important to understand that the triple test is a screening test and not a diagnostic test. This test only notes that a mother is at possible risk of carrying a baby with a genetic disorder. The triple screen test is known to have a high percentage of false positive results. They merely show a probability and may be an indication for additional testing.
A more conservative approach involves performing a second triple screen followed by a high definition ultrasound. If the testing still maintains abnormal results, a more invasive procedure like amniocentesis may be performed. Invasive testing procedures should be discussed thoroughly with your healthcare provider and between you and your partner.
Additional counseling and discussions with a counselor may prove helpful.
Is there any risk associated with the Triple Marker Test?
The triple screen is a routine prenatal screening test. The test poses no risk of miscarriage or other pregnancy complications.