Quadruple Marker Test Low Risk Means
Kanisha Dezarn
The quad marker screen is a blood test that provides useful information about a pregnancy. It can help estimate your baby's risk of Down syndrome, Edward's syndrome (trisomy 18), and neural tube defects.
The test predicts the likelihood of a problem. It does not diagnose the problem. The quad marker screen determines if a woman is at higher or lower risk of carrying a baby with a birth defect. This means that some women with healthy babies will have screening results indicating a possible problem (and will be offered appropriate follow-up testing), while some women whose babies have birth defects will go undetected.
The quad marker screen has replaced an earlier test, the triple screen, in the U.S. Doctors sometimes combine the results of the quad test with the first trimester screening. This is called integrated or sequential screening. It's more accurate than either test by itself.
The expected amount of these substances normally found in the mother's bloodstream changes weekly during pregnancy, so it is important to tell your doctor how far along you are in your pregnancy. High AFP levels may indicate that the baby has an open neural tube defect. High AFP levels may also indicate that the baby is older than was thought or that the woman is expecting twins. Lower than normal AFP levels could indicate that a woman is at higher risk for having a baby with Down syndrome.
Levels of hCG and Inhibin-A are higher than normal when a woman has an increased risk of having a baby with Down syndrome. Lower than normal levels of estriol (a hormone) may also indicate that a woman is at high risk for having a baby with Down syndrome.
Down syndrome is a condition in which a person is born with an extra chromosome or an extra piece of a chromosome. The condition causes problems with development, thinking, learning, and physical health. Down syndrome tests can help find this chromosome disorder in unborn babies.
Chromosomes are tiny "packages" in your cells that contain your genes. Genes carry information, called DNA, that controls what you look like and how your body works. Normally, you're born with a set of 46 chromosomes in each cell. The chromosomes are grouped into 23 pairs. Each pair has two chromosomes, one coming from each parent.
Most people with Down syndrome have an extra copy of chromosome 21 in all their cells. This common form of Down syndrome is called trisomy 21. "Trisomy" means having three copies of a chromosome in your cells instead of the usual two. With less common types of Down syndrome, a person may have:
The extra chromosome affects the way a baby's brain and body develop. The symptoms may range from mild to severe. Children with Down syndrome usually have some problems with thinking and learning. They may start talking later than other children.
Common physical signs of Down syndrome include a flat face, eyes that slant up, a short neck, small hands and feet, poor muscle tone, and loose joints. Common health problems in childhood include hearing loss, sleep apnea, ear infections, eye diseases, and heart defects.
For a blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
For the first trimester ultrasound, a health care professional will move an ultrasound wand-like device on your belly. Ultrasound uses sound waves to make an image of your unborn baby.
For chorionic villus sampling (CVS), a provider collects a sample of tissue from the placenta with either a needle that's inserted through your belly or a tube that's inserted through your vagina.
For percutaneous umbilical blood sampling (PUBS), a provider inserts a hollow needle through your belly and into the umbilical cord in your uterus. A small blood sample is removed from a vein in the cord.
PUBS may cause brief discomfort. This test has a slightly higher risk of causing serious problems than amniocentesis or CVS. Talk with your health care provider about the risks and benefits of testing for Down syndrome.
Whether or not your screening tests were normal, you may choose to have one or more diagnostic tests. Diagnostic tests can usually tell you whether or not your baby will have Down syndrome. But diagnostic tests cannot predict how much Down syndrome will affect your baby's health and abilities.
You may find it helpful to speak with a genetic counselor before testing and again after you get your results. Genetic counselors are specially trained to help you weigh the risks and benefits of testing. They can also help you understand and what your results mean so you can make informed decisions.
The quad marker screening test (quad screen) is a blood test administered in pregnancy, typically between the 15th and 20th weeks of gestation. Similar to the triple screen, the quad marker screen provides information about whether there is an increased risk for certain birth defects in the baby.
The test is simple and involves taking a blood sample as for any other routine blood test. The quad marker test is a screening test, meaning that it gives information about risk, but it does not allow the definitive diagnosis of any conditions. It can only signal that further testing should be done to confirm a diagnosis. There is no risk to the baby from the test.
The test is a screening test only, and is not 100% accurate. It can predict about 85% of open neural tube defects, problems with the development of the baby's brain and spinal cord. It predicts about 80% of fetuses with Down syndrome in women over age 35 and about 75% in younger women. The fact that it is not 100% accurate means that not all women who have a positive high risk result on the quad screen will have a fetus with a birth defect, and the test may also be normal even in the presence of birth defects.
For example, about 50 women out of every 1,000 will have a result on the quad screen that indicates an increased risk of a birth defect, but only one to two of those women will actually have a baby with an open neural tube defect. About 40 women out of 1,000 will have a result indicating an increased risk of Down syndrome, but only one to two of these women will have a baby with Down syndrome.
As with any screening test, an abnormal result does not mean that the fetus definitely has a birth defect or genetic condition. It only means that the blood levels of these four substances suggest that a woman's risk is increased of having a baby with certain conditions. Women who have a result suggesting increased risk are typically offered further testing. This can include repeating the quad screen and/or having a high definition ultrasound examination to look for signs of birth defects or abnormalities in the developing baby. If this testing is abnormal, the mother may be offered the choice to undergo amniocentesis. Amniocentesis involves withdrawing a sample of amniotic fluid for genetic and chromosome testing, and it can definitively establish the diagnosis of genetic and chromosomal problems in most fetuses. Amniocentesis carries a small risk of miscarriage (fewer than 1% of fetuses tested).
Preeclampsia is a condition in pregnant women marked by high blood pressure and a high level of protein in the urine. Eclampsia occurs when preeclampsia goes untreated. Eclampsia can cause coma and death of the mother and baby. Preeclampsia symptoms include rapid weight gain, abdominal pain, headaches, blood in the urine, dizziness, and excessive vomiting and nausea. The only real cure for preeclampsia and eclampsia is the birth of the baby.
Blood tests are a standard diagnostic tool during pregnancy. It is a safer option which provides a clear picture about the factors affecting the growing fetus, and allows the would-be parents and the doctors to stay informed about the fetal growth, development, and associated anomalies.
The quad marker test results also flag if there is a possibility of severe developmental complications in the baby, requiring further testing. Given how important the test is, knowing about it in detail enables the parents to make informed decisions during their pregnancy.
The prevalence of quad marker screening has been around for a long time. It is part of prenatal care and is an important test that prepares the would-be parents for any complications that could affect the baby after their delivery.
The quad-marker screening analyzes and helps estimate four conditions:
The Quadruple Marker Test, also known as the Quadruple Screen Test or Quadruple Marker Screening, is a prenatal screening test used to assess the risk of certain chromosomal abnormalities and neural tube defects in the developing fetus. It typically measures four substances in the mother's blood:
The purpose of the Quadruple Marker Test is to provide information about the likelihood of conditions such as Down syndrome (Trisomy 21), Edwards syndrome (Trisomy 18), and neural tube defects like spina bifida or anencephaly. While the Quadruple Marker Test does not provide a definitive diagnosis, it helps identify pregnancies that may be at increased risk, allowing for further diagnostic testing or counseling to be offered to the parents. Overall, the test aims to provide expectant parents with valuable information about the health and development of their unborn child, empowering them to make informed decisions about their pregnancy and prenatal care.
As mentioned before in brief, the quad marker screen addresses four distinct factors. The low and high levels of these individual factors depict the risks of the birth defects in the developing fetus during pregnancy.
Also, there are no specific requirements needed for preparing for the test. The mother can get their blood drawn after eating or even following their medication. There are no imposed restrictions on the timing of the test too.
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