Lurker with a question

lalee73

Hi ladies, usually I post over on paif but have a question that may be more suitable over here.

Recently had nt scan don which came back perfect, but blood work put us at 1/20 risk of downs.    We went ahead and did the materniti21 test because at that point an amnio was to scary for risk of miscarriage.  Just got the call today that it was positive.  Needless to say that we are devastated.  I know life isn't fair, but this just seems like a double dose of unfairness after years of infertility.  Right now we are going to go ahead with the amnio for a definitive diagnosis.

I guess what I want to know is, does anyone know of or have had a positive materniti21 with negative amnio.  Is that even possible?

Thanks for your responses in advance. 

danieleandwayne

From what I understand-- and I haven't had my MaterniT21 test yet-- the test is determined positive or negative based on a scale that can differ by one number. So you can be positive-- by one number. I know that the test is supposed to be 99% accurate, but I have to question what that means if you can be positive or negative based on one increment.

I'll be curious to hear what others say in response... Hang in there! Nothing in medicine is 100%-- it's why they call it "practicing medicine!"

ShellBear+

So sorry this has happened. I don't know the answer but it's also my understanding that maternit21 is extremely accurate. My heart goes out to you and your dh.

danuli8

I'm so sorry this has happened to you. I have read around a lot about MT21 on several boards (there is a whole board at BabyCenter that is just MT21 stuff), and I have only ever heard of one false negative and one false positive in several months of reading around. I would go ahead with the amnio and pray that you are false positive #2. My DH and I agreed that we would do an amnio to confirm if our results came back positive. (They didn't, so no amnio for us.)

jennyandjasonsbaby

I just posted on the May 2013 board asking if anyone had experience with the Harmony test (pretty much the same at the Martenit21 test. 

My doctor explained to us that with the blood work it's all based on a scale and your age, so when you are 35+ your number increases for a positive.  He explained that the Harmony or Materni21 tests are more accurate but they can still give false positives.  Keeping you in my thoughts and prayers, please let us know how you make out.

PipSqueak0313

New to this board but had to respond to this.

I am 42 and had a positive MaterniT21 test as well in mid-September.  FWIW, dh turns 58 next week.

Dh and I decided the odds were more in favor of the test being correct so we decided to prepare for having a baby with down syndrome and if his birth proves he does not have ds then we'll adjust the plans based on that, though I think at this point I'd be disappointed if the test was a false positive.

I've already talked to the people in our local ds support group -- the parents of a child with ds are really the best sources of support and information at this point as they understand the emotional roller coaster that the news throws you on.

 

 

juliew77

I am late to this discussion but just joined today. I am waiting on my results for my maternit21 test (1 in 59 odds). I did a lot of research trying to understand what all of the numbers mean, but in the end, maternit21 still has a false positive rate of somehwere between .2% and .5%. Yes it detects 99.1% of all cases but these two things are seperate. Lets take the .2% false error rate to be conservative. If you had 10000 people tested, there would be between 20 false positives. If the odds of having a DS baby are around 1 in 50 for this group (since only high risk people take the test) then 200 of the 10,000 have a baby with DS. Since the test is 99.1% accurate, the test would find 198 of the cases but miss 2 cases. SO what all this means is that they test results would indicate a positive for 218 people (the 198 they caught plus the 20 false positives). So the chance that your test results are a false positive is something like 10% (20/218). That is why many people follow up a positive result with an amnio especially if ultrasounds don't give any hard markers.

Maybe this was really clear to people, but when I first got my screen results I struggled with what a false positive meant on a probability. I was confused how so many people were given false positives but yet the false positive on the sequential screen is still only 5%. I was looking at it as 5% of the people told they were high risk, not that 5% of everyone tested were part of the false positive group.

I hope the best for you and your baby. I am sure you will love the baby the same, but dont we all want the best for our children? Just read a great book - Expecting Adam about a Harvard couple that had a baby with DS and how it changed their life in a great way.