verify couldn't test the second sample either, citing the same problem as the first try (too much maternal DNA in the sample, or something like that). so twice a bust with verify, but got the negative from materniT21. my GC remains very suspicious of the materniT21 result since verify can't even test my samples. i still don't know how different the labs and their technologies are, if at all. at this point it is almost irrelevant. without an amnio we just don't have certainty. but heck, is there any certainty in life?!
When I had my nuchal screening done I was told those measurements are very important. I was told not to worry about the bloodwork because my measurements were nice and thin. They also look at other things in the ultrasound. My bloodwork came back just fine as they predicted it would.
It is just a screening test but I wish they could have told you a bit more to put your mind at rest. Feel good about the measurements.
Just because the measurement is "good" doesn't mean no DS. The measurements are important yes, but the reason the nuchal scan is done IN CONJUNCTION with blood, is to get a more accurate picture for DS and trisomies 13 and 18. Not to scare you or anyone but I just went through this and had been so excited for a good measurement, but then my blood came back high risk. A DS baby CAN have a "good" nuchal measurement.
Do many women of AMA receive false positives for their nuchal scan? Yes. It's NOT a dignostic test, it just exists to tell you odds and so that if your odds are HIGH you can make a choice as to how you would like to proceed with additional testing (or not)
I just want people to be informed of this in case they think "oh my measurement was good, I don't have to worry" You need to get the measurement AND blood, see what the two combined tell you and then decide if you want either to leave it all alone and not do anything, or go on to have a CVS, Amnio or MaterniT21.
I know I have gone on and on about this...I will shut up from now on
The NT measurement is not useless without the b/w, but it just can't give you numerical odds. It DOES mean that your risk is lower than others your age, but just not how much lower. Your NT measurement was good and your b/w revised your risk to be lower than others your age. Not as low as you hoped but still lower (and the test isn't as conclusive for women your age either). Having a good, NT measurement, 4 limbs and a nasal bone are all good signs even w/o b/w. no, it doesn't mean no DS, but neither does a negative mat21. It's only 99% accurate.
Having 4 limbs is good but has nothing to do with whether or not a baby has DS. And also while it is good to see a nasal bone, some babies with DS do have a nasal bone. A good nuchal measurement is not a bad thing but just not enough to conclude no down. Of course you are right about the maternit21 test, as someone who had it I realize just because I got a negative doesn't mean my baby won't have down. My point was that you need the blood with that measurement to better decide if you want to proceed with further testing. You just can't say I had a good measurement I'm in the clear. That's all I am saying.
Only 60-70% of DS children have abnormal nuchal measurements. That means 30-40% of ds babies have normal measurements. So in actuality those are not as great odds as the Materni21 test or similar. So the nuchal on it's own doesn't give a huge amount of reassurance. I agree with Theresa, and not trying to freak people out, but a normal nuchal is only a part of the picture.
Case in point, for a previous pregnancy we had a 1.7 measurement and got 1:7 odds on the blood test, so the blood actually is weighted a lot more. I was pretty shocked. The baby did not have down's, but did have a severe heart problem.
This was what my GC told us. You CANNOT go by the nuchal measurements alone. You have to do it with the blood work, and yes, if you are AMA they often come back high risk, but then you have the option to further test...
I also don't want to freak anyone out, god knows I have been there and it sucks..but I also want people to be aware so they can make the decision with how to proceed with further testing.
If you are in this situation please speak to your genetic counselor. They are professionals and the best person to discuss your results with. XOXO
But a good measurement is an indicator that things are ok. I was actually given the option as to whether I wanted to proceed with blood work and I chose the blood work to complete the screening process.
From what I've been told, the false positive rate is not just high for women who are AMA- it is true across women of all ages. The risk ratio go up somewhat based on age alone for women who are AMA, but that is expected given the actual overall odds risk r/t age. However, false positives are very common for women of all ages (and even more so for women who did IVF d/t higher HCG and lower PAPP-A levels especially for the "part I" tests- some labs take this into account and others do not which is something to be aware of). Just wanted to add some info I got from our local genetic counselor in case women who are not AMA look at this later on... Overall though I agree with you- it's really not a fabulously accurate test and hopefully in time will be replaced by the fetal DNA testing once the technology is more proven/perfected.
"the false positive rate is not just high for women who are AMA- it is true across women of all ages"
This statement from Erin is so true and I am living proof. With my DD's pregnancy 4 years ago, my odds from the NT bloodwork screening were WAY worse than they were for this pregnancy and I'm 4 years older now. I was 33 at the time and given a 1:105 chance of DS. The nurse and genetic counselor also told me that the false positive rate for this screening is high. (Ultimately, I had an amnio b/c I couldn't deal with that stress and anxiety.) Needless to say, my DD is perfect and healthy.
I think once this result is combined with the quad screen, then it paints a clearer picture and gets even more clear with the anatomy/level II scan, if people don't feel comfortable with the invasive procedures.
Regardless, it can all be so frustrating. Wishing you the best, Broody.
The test is actually less good at detecting ds in younger women, and thus there are different risk categories depending on age. So if you are younger you may be flagged at high risk if your odds are 1:250 whereas not if you are older. My odds were 1:208 and surprisingly they called this negative.
I think saying false positives is a little misleading since you are given odds, so you would expect most people to be negative even if they were flagged as high risk. the question is where they put the high risk category and will this detect most of the ds cases.
The test is actually very good for this and will catch greater than 90% of the ds cases, and I think greater than 95% if you are AMA.
I do not think that the quad screen improves those odds, so that is why you should think before doing it. Case in point there was a case here where they got something like 1:50 odds from the nuchal, did the quad,afp or whatever, and got better odds so they were reassured the baby did not have downs. The baby did in fact have downs. So false negatives can be a problem too.
True, it can come back as high risk for anyone of any age but again, reverting back to my own experience, the info we received- (and this was told to me because I am AMA and our GC has seen false positives in so many many times in women over 35)
'Most clinics use the age risk for a 35 year old as the cut off for a positive screen. Age risk is the main driver of the final risk and this is why it is relatively difficult for a woman over 35 to screen negative for DS. The cited 5% false positive rate becomes more like a 40-60% (depending on study) false positive for women over 35.'
I wish someone had warned me about this before the test, really I was very uninformed about the entire process. I thought the nuchal measurement was the be all end all, I really did. I didn't understand. And I wish I had been sent to a Genetic Counselor BEFORE I even had the nuchal frequency...so that I wouldn't have freaked out so much when I came back high risk.
I hate this stupid test and I wish anyone and everyone the best with it.
the point of the test. They wanted to develop a screen that would identify babies at risk for ds. Prior to this, many more people (particularly AMA women) were getting amnios, which caused many more m/cs. So they wanted to develop a test that would cut down on the number of women getting amnios and cvs. So it has done this quite well and a lot of babies have probably been saved.
The study I read had a 13% false positive rate at 1:200 for AMA, which dropped to about 6% when they dropped the high risk category to 1:100 (so according to this you should not have been flagged as high risk). 40-50% sounds high.
But I agree, women should probably meet with a GC before the test, so they can understand it. Or the OBs should understand it better, and be able to explain it better. It may all be moot soon with these other tests.
Why the MatereniT21 would come back negative...wouldn't it come back inconclusive? Or even positive, because our GC told me IF the MaterniT21 test comes back positive, she would have advised to go ahead with an amnio (I still would NOT have)
Broody, have you called Sequenom and told them of this? Maybe they can give you more of an explanation/insight and put your mind at ease?
I am SO sorry this is causing you so much stress, I really feel bad. When is your next scan?
Again, I would take solace in that it came back negative AND they havent seen any soft markers. Keep your eye on those odds in your favor, which are very, very high.
If you need the # to Sequenom, please let me know, I have it.
Hi Broodyhen- It's frustrating that the second sample came back the same as the first, but I'm really glad you're feeling good anyways b/c I do think there are good reasons to be optimistic! I second Teresa's suggestion to call Sequenom- I called them once and also found them helpful. There may be a very good reason why their test would have a result where verify did not (the technology/machines used in the process may very well be different, etc.).
As for the sequential screen (NT scan/labs) I keep bringing her up, but my midwife friend (who is very evidence-based and up on research) really does not like that test. She encouraged me to skip it and I wish I would have taken her advice ultimately. She feels that it's not really very accurate and has a lot of false positives (for all ages of women)- although she's quick to point out that there are no "positives" or "negatives" with that test- as an odds ratio, the result is not all that telling or accurate. She said she's seen women with very high odds for DS (like 1:3) end up w/ a completely healthy baby, and a woman with 1:1000 odds of DS have a baby with DS. She feels that the test tends to cause a lot of unnecessary worry (or in the latter case, inappropriate relief) and I'm tending to agree.
So, all that to say I think you have every reason to feel optimistic with the negative MaterniT21 test! You are absolutely right on there being no certainty in life- hard to accept (especially after dealing with years of IF) but very true. Sending good thoughts!
Would have been nice to have a second reassurance. I did do a bit of research on the different tests when you listed them below to see if they do things differently (I am in genetics research so these things interest me!). Harmony had a nice website explaining things and it seems the MaterniT21 test uses Massive Parallel Sequencing, whereas Harmony uses more direct sequencing (although they didn't explain), I couldn't figure out how Verify does it. Anyway, Harmony claims their method is more sensitive so potentially you could get a result from them? Just a thought.
You are probably done with all this and I agree, if you feel ok then go with it. I am a bit the same as I didn't get the greatest odds on the nuchal but I think I can live with the small chance that the baby has ds. I have the level II tomorrow so I guess if they pick up some markers I will have to reevaluate.
Definitely no certainties in life, heck autism rates are around 1:60 for boys but nobody stresses about that because we can't test for it. Hang in there!
thanks for the replies and lively discussion! it is hard to process the odds and statistics. i scheduled an amnio. i can always cancel. but right now it feels good to know i've got the appointment and the choice.