I think this is the test:
FTS is a non-invasive screening test carried out on maternal serum obtained in first trimester pregnancy (between 11w0d and 13w6d gestation), to provide a service involves a risk calculation derived from combination of two biochemical placental markers; free Beta hCG and PAPP-A combined with the ultrasound marker Nuchal Translucency (11w0d-13w6d gestation) for the screening of the three most common fetal chromosomal abnormalities, namely, Trisomy 21(Down’s Syndrome), Trisomy 18 (Edwards’ Syndrome), and Trisomy 13 (Patau’s Syndrome). Detection rate >90%1
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What is the test for????
Why test for Down's syndrome?
Down's syndrome is the most common chromosomal abnormality and can have a major impact on a family, so testing for it in pregnancy have been available for some time. Tests are especially offered to pregnant women over the age of 35. Older women are more likely than younger ones to have a baby with Down's syndrome.
There are two types of test available. A screening test estimates the risk of your baby having Down's. A diagnostic test, such as CVS or amniocentesis, can give you a definite diagnosis, but also carries a small risk of miscarriage.
What screening tests are available?
There are many different screening tests available in the private sector (but not in government hospitals or clinics). You will have to pay for them.
There are ultrasound tests, blood tests and a combination of the two. Remember that these are screening tests. They can't tell you for certain that your baby has or has not got Down's syndrome. A screening test can help you decide whether or not to have a diagnostic test.
A cut-off point of 1 in 250 is usually used. If your risk is less than that, you will be described as "screen negative" which means that you are unlikely to be carrying a baby with Down's (but it's not impossible). The tests will detect many pregnancies affected by Down's syndrome, but they will also identify some pregnancies as being at risk of Down's syndrome when, in fact, they are not; these are known as "false-positives".
First trimester screening
From 11 to 14 weeks of pregnancy, an ultrasound scan called a nuchal translucency (NT) scan can be performed. During an NT scan, the doctor measures the fluid under the skin at the back of your baby's neck. This can be used to determine your risk of having a baby with Down's syndrome.
There is also a blood test which you can have either in combination with the NT scan (the combined test) or on its own. The blood test measures:
hCG (human chorionic gonadotrophin);
PAPP-A (pregnancy associated plasma protein).
A woman who is carrying a baby with Down's syndrome will have abnormal levels of these two substances in her blood.
These tests are pretty accurate on their own but become even more accurate if combined. The NT scan alone probably picks up about 75 to 82 per cent of babies with Down's syndrome, and the blood test alone, about 60 to 70 per cent. If you put the two tests together, the detection rate is usually in the range of 90 to 93 per cent with about a 3 to 5 per cent false positive rate.
However, the accuracy of the combined test depends on many factors, such as the training of the person performing the scan and how good the scanner is that she's using. Plus the timings of the blood tests and the NT scan can also make a difference to detection rates.
Advantages of first trimester screening
Good detection rates.
You have time to think about what you want to do next if you are found to be at high risk for Down's.
Your options include doing nothing or having a diagnostic test, such as CVS or amniocentesis, to tell you for certain if your baby has Down's. You, your husband and doctor can then discuss the next course of action.
Disadvantages of first trimester screening
NT scans are not available everywhere, and many doctors are not accredited or suitably trained to perform them.
The combined NT and blood test is only available in the private sector and is expensive.
The nuchal translucency test will also check whether your baby has a visible nasal bone. In the past few years it has been seen that approximately 3 in 4 babies with Down's syndrome do not have a visible nasal bone at the time of the first trimester screening test. If the nasal bone is visible at the scan then this will reduce the chance of your baby having Down's syndrome.
1 comments:
where did u do the test?