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The Quad Test
The Quad Test (formerly the Triple Test) is a blood test that can help identify babies that may have certain birth defects.
Conditions that the Quad Test can help detect include Down Syndrome, Trisomy 18, spina bifida, anencephaly, ventral wall defects and Smith-Lemli-Opitz syndrome.
The test is not effective for twin or triplet pregnancies. For those who choose to take the test, a blood sample is
collected between 15 and 22 weeks of pregnancy.
The test uses the levels of four pregnancy hormones in the blood to predict whether the chance of a birth defect is average, above average, or below average. If the results suggest an increased risk
of a certain birth defect, you will be given options for further testing. These options may include another blood test, an ultrasound examination or possible an amniocentesis to give you accurate information regarding the health of your baby.
Fortunately, most babies are normal and the Quad Test indicates average or below average risk for a problem. If the results is an above average risk, however, remember that most babies are still normal.
About 19 out of 20 babies with an "abnormal" Quad Test report will be found to be normal after additional testing is complete.
Serum Integrated Test
The Serum Integrated Test adds an additional blood sample, drawn between 10 and 13 weeks of pregnancy, to the Quad Test. By combining the result with the other four, the Serum Integrated Test cuts in half the chance of getting an "abnormal" result
(and thus the need for further investigation) while improving its ability to identify those pregnancies that have a problem.
Who Should take the Quad Test or Serum Integrated Test?
Since the Quad Test and Serum Integrated Test can neither diagnose a birth defect nor guarantee the absence of a birth defect, the reason to take either test is to determine whether a diagnostic test, such as amniocentesis, would be helpful
to learn more about the health of the baby. Since amniocentesis is an invasive procedure that can cause a miscarriage in one out of every 200 or 300 cases, parents must decide if the information the test provides is worth taking the small risk to obtain it.
The desire to have advanced knowledge of birth defects varies among families and even between pregnancies within a family. A few groups of typical parents and the choices they make are described below:
- Some people are very interested in having as
much information as possible early in pregnancy so that they can feel
that they are making well-informed decisions. They might consider
terminating the pregnancy if it is severely affected, or they may wish
to become better informed about the birth defect and to prepare
themselves to care for a child that will have special needs. People in
this group usually feel that it is important enough to have this
information to take the small risk of miscarriage associated with
amniocentesis. The Quad Test or Serum Integrated Test is a good way for them to find out if an amniocentesis would be necessary to learn more about their pregnancy.
- Others feel that knowledge of a birth defect
would not change the way they would approach their pregnancy. They would
not consider terminating the pregnancy for any reason. People in this
group usually feel that the risk of miscarriage associated with
amniocentesis far outweighs the value of the information it could
provide. They do not usually need to consider the Quad Test or Serum
Integrated Test, as the results would not change their plans during the
pregnancy.
- A third group of parents are those who feel less
certain about how the results of the Quad Test or Serum Integrated Test
would affect their pregnancy plans. They might be strongly interested in
having information about their baby's health, yet be reluctant to accept
the risks associated with amniocentesis. They often have received much
advice from friends and relatives but still feel undecided about what
makes the most sense for them. People in this group often reach a
decision by asking themselves which would be worse:
- to have declined testing, later to discover that their baby had a detectable birth defect, or
- to have taken the Quad Test of Serum Integrated Test, undergone an amniocentesis, and experienced a miscarriage of what was most likely a normal pregnancy
Knowing what the least worst choice is can help make a difficult decision a little easier to make.
It is important
to keep in mind that the Quad Test and Serum Integrated Test are only tools to help decide who should be offered further testing. The tests do occasionally indicate an increased risk of birth
defects in pregnancies that have normal babies. Receiving an abnormal test result is very distressing to parents and the reassurance that everything is okay can require undergoing amniocentesis and waiting for two to three weeks for the final results. Before taking either test, consider the possibility of a false-positive test result and your willingness to undergo further testing.
Note: This information applies only to Lansing OB/GYN Associates.
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