Brief Answer: do not worry. Detailed Answer: Hello and welcome, It seems that you have undergone some investigations that place your risk ratio as 1:153 and then the NT scan that gave a normal result. Now you want to combine the results of the two for risk assessment. It would help me immensely if you could inform me what were the tests that were done and at what gestation, what will be your age at delivery for providing a better opinion. There are various types of tests for screening Down's syndrome and they are done at different times. These include integrated tests that test that uses first trimester and second trimester markers as well as NT, serum integrated is also 2 step using blood markers, combined test uses first trimester markers as well as NT, other tests are quadruple test and quadruple test with NT and are done in first and second trimester. All of them use different calculators to estimate the risk. So it will most likely not be possible to do it ourselves as the soft wares are usually with the labs that do the tests. The integrated tests is considered to be the best for screening with lowest false positive rates and highest rates of detecting Down's. However you must understand that these tests only say that you are at higher risk than the general population of having an affected baby. It does not mean that you have an affected baby. The Odds of actually being affected after a screening tests is positive are different. Means that every individual that screens positive will not have affected baby. For example the odds of affection with integrated tests is 1:5. This indicates that only 1 out of 5 will actually have the disease. So if screening is positive a confirmatory test is done. This includes: 1. amniocentesis or collecting the amniotic fluid and genetic analysis of that to actually see chromosomal defects. This is good confirmatory test. 2. chorionic villus sampling: done at 11 weeks 3. detailed ultrasound scan at 18-20 weeks. Not very accurate. So please inform to me all the tests and at what gestation they were done. [it would help immensely if i knew the dates of your last period and dates of tests]. I can provide the interpretations of the tests but will most likely not be able to provide combined risks as not all tests results can be combined. So one thing that I want to assure you is not every screen positive is affected. So there is no need to worry. Just inform the results so that I may help you with a better opinion. Hope this satisfies your query. Thanks for using HCM. Feel free to ask any more questions that you may have. Dr Madhuri Bagde Consultant Obstetrician and Gynecologist

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Brief Answer: detailed answer below. Detailed Answer: Hello and welcome back, I understand the issue completely. First let me address the issue of dates. Sometimes there is a bleeding called implantation bleed that occurs during the attachment of the baby with the mother. This is not a period and occurs after the last menstrual period creating a confusion of dates. So please follow the ultrasound dates as they are accurate in the first three months. Now about downs syndrome. Blood tests are more reliable then NT scan but they are not accurate. They will just say that there is more risk of having a disease. They will not say that the disease is actually there. So genetic tests will be most accurate in providing information. About the combined risk assessment. Integrated tests need the following parameters. alpha-fetoprotein (AFP) total human chorionic gonadotrophin (hCG) unconjugated oestriol (uE3) inhibin-A (inhibin) You have provided me with only 2 of these. It is not possible to calculate risks using pen and paper as the calculations weigh many different probabilities and are extremely complex. however there are certain online calculators that provide risk assessment based on the few reports available. A combined test assesses 1.pregnancy associated plasma protein-A (PAPP-A) 2.free ß-human chorionic gonadotrophin (free ß-hCG) 3. nuchal translucency (NT). However they are assessed at the same time between 10-13 weeks. So your results are not valid as they are tested at different times. However I have tried a rough calculation using an available calculator. the risk of Downs comes to 1: 404 But these calculations cannot be taken as a guide for therapy as the information provided is not a per the standards required for calculating the risks. So as of now I must say that one of the important parameters AFP has not been tested. so get it tested. Also ask the labs that tested for a combined risk as they have softwares according to the specific parameters and can help you. Also communicate the same with your doctor and she will help you get information from the lab. If you are scared to do an amniocentesis get a detailed ultrasound scan at 18-20 weeks. If it is Ok the risks are lower. Please do not worry. The risk is less if NT is normal. Please feel free for any more queries. I am here to help. I do understand your concern. Please do not worry. Dr Madhuri

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Brief Answer: Answers provided below. Detailed Answer: Hi and welcome back. I do understand your concern. Hypothyroidism does not contribute to it but mothers age is the single most important risk factor. The screening policies differ in various hospitals and they have their own risk models based on those screens. A single hormone or marker will not give any information as it is elevated in so many conditions so a combination is important. The table below provides the different tests available and their efficacy. Test Cut-off Detection rate False Positive Odds of being affected given a positive result Integrated 1 in 150 90 1.3 1:5 Serum Integrated 1 in 150 82 2.7 1:12 Combined 1 in 150 84 2.2 1:9 Quadruple 1 in 150 80 3.5 1:15 Quadruple plus NT test 1 in 150 80 1.6 1:6 So you can see how things are. for example an integrated test will detect 90% of cases. It will miss 10% and 1.3% will not be have downs but will still come positive. When the test is positive the 1 in 5 babies will actually have downs. The combinations and risk ratios are different in various labs. Please contact your lab and ask them for the tests results according to the various tests and their interpretations. Then only it will be possible to compare between tests. A really detailed ultrasound scan will also be very helpful as a skilled sonologist will be able to pick up markers easily. So I suggest that as of now you please wait for the next set of tests and see how risk spans. There are a very tiny percent of women in whom one test is positive and others negative. Usually if the baby is affected most tests do give a positive screen result. If the next set of test gives a negative result then chances of actually having an affected baby are very low as the false negative rates of tests is not usually very high. So all my best wishes are with you. Do not worry. Just wait for the results and scan. I am always hear to help you. Regards Dr Madhuri

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