Info I found online on it: Genetic testing, of any sort, usually brings a large debate. The alphfetoprotein (AFP) or triple screen are no exceptions.
The AFP test, sometimes called the MSAFP or maternal serum AFP, is where a blood sample is drawn from the mother to check the levels of AFP. AFP is a protein secreted by the fetal liver and excreted in the mother's blood. It is generally used for detecting neural tube defects, but it can also indicate: abdominal wall defects esophageal and duodenal atresia, some renal and urinary tract anomalies turner syndrome, some low birth weight fetuses, and placental complications. A low level of AFP could also indicate Down Syndrome.
The triple screen measures not only AFP, but hCG and estriol as well. This test is more accurate and screens for additional genetic problems, and is beginning to replace the standard AFP. Generally speaking, any combination of the testing will identify 60% of the babies with Down Syndrome and 80-90% of the babies with neural tube defects..
The controversy in these tests lies in many places. One of which is the accuracy of the screenings. While some claim that they have only a 5% 'false positive' rate, most research finds that there are 80+% rate of positive tests while the baby is unaffected. The false positive rates depend on many factors, including appropriate gestational age, maternal age, weight and the presence of diabetes.
False positives may not seem like a problem, however, there are follow up tests that are done that do carry risks, like amniocentesis, which does carry a 1 - 2% rate of fetal loss. The standard is usually to repeat the AFP or triple screen. Another positive screen will then go to the Level II Ultrasound. Ultrasound can even be used to detect some of the anomalies associated with Downs Syndrome. If the ultrasound doesn't find a mix up in gestational age, or a multiple pregnancy, an amniocentesis is generally the next step.
There is a possible benefit of identifying neural tube defects before birth, because that can alter care. Such as the mode of delivery. It is generally considered safer for a baby with spina bifida to have a cesarean delivery. Although this can also be identified by ultrasound alone.
It has been estimated that every positive screening will cost approximately $106,000.
Of the positive test results, 90% of these babies will not have any anomalies. There may be other benign reasons for the elevated or low levels of the hormones, specifically the gestational age, or multiple pregnancies. The AFP test is generally done between the 16th and 18th weeks of pregnancy, while the triple screen can be done a bit earlier. The gestational age is very important, because the amount of hormone in your blood will vary with gestational age.
The American College of Obstetricians and Gynecologists have stated that they believe this test should be offered to all pregnant women, regardless of maternal age. However, many women are made to believe the testing is mandatory. Many who refuse are asked to sign waivers in order to not take the test. While others are finding that their insurance coverage has a part to play in the whole scenario.
The test results are generally given as either positive/negative or a risk ranking, such as: 1/47 chance of having a baby with X anomaly. As well as low/high rankings. It is important to remember that being at an increased risk does not mean your baby has the defect. You should also ask that your practitioner explain the results in detail to you.
Samanthas Mom
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Re: What is an AFP ? Test
Thanks my dr. tested both our blood for cystic fibrosis and some type of Jewish screen panel? everything turned out okay though, although I had a scare for like two weeks until DH went b/c my blood came back that I was an auto recessive carrier of CF but I do not have it but carry it they said he had to be tested right away b/c there are four different cf mutations and if he had the same one as me, there was a 1/4 chance the baby could have it, but all his tests came back negative, thank God for everything so the Dr. said the baby will not have CF. Now, DH teases me that he has good genes and I dont! but at least now we know there is no chance this baby or any others will have CF.
Teri
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Re: What is an AFP ? Test
Was the Jewish thing Tay Sachs? I think I read that somewhere.
AFP also tests for Spinal Bifida I think.
I was going back and forth with this because of the high false positive rate. I really don't want an amnio which is what they'd do if the test came back positive, so then I thought, why bother testing in the first place?
I'm going to talk to my dr at my appt tomorrow but will probably just end up taking it anyway!
Samanthas Mom
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Re: What is an AFP ? Test
Posted by Teri
Was the Jewish thing Tay Sachs? I think I read that somewhere.
!
I am not sure - I think that and others, the lab thing just said Jewish Panel Screen and CF since it only required giving some blood I did not mind. My dr. said that CVS and AMnio's if needed run risks of miscarriage so that is why she sent us for blood work early on just to be safe
rlivings
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Re: What is an AFP ? Test
The Jewish Screening is Tay Schs and 3 other diseases that carry in Ashkenazi Jews. It is routine for Jewish parents. My husnand is not Jewish but they did it for me anyway.
We did not have the AFP test. Firstly, it is pretty useless for multiple births. As innaccurate as it can be for singletons, it is totally inaccurate for multiples. Additionally, my husband and I knew that it wouldn't make a difference to us either way. If the baby or babies had DS, we would not terminate the pregnancy so what will be will be.
We were testing a little extra for spina bifida because my DH first cousin has it but everything looked good.
My girls will be arriving any day now. I am 37 weeks today!!!
chmlengr
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Re: What is an AFP ? Test
Posted by Teri
I was going back and forth with this because of the high false positive rate. I really don't want an amnio which is what they'd do if the test came back positive, so then I thought, why bother testing in the first place?
I'm going to talk to my dr at my appt tomorrow but will probably just end up taking it anyway!
Teri- if your test for AFP comes back positive, the next step is usually to screen out the abnormalities during your level 2 sonogram, so having amnio is a last resort, if you wish to have it.
