Harmony Test - false neg/pos?

[Luckygirlcharlie]

Hi. Just wondering if anyone has had, or knows anyone who's had a wrong result from Harmony? I had it done with DS and was very reassured. Will be having it again this time if I get to 10 weeks (only 5 now) but just wondered how reliable it really is. Thanks.

I don't know any one who has incorrect results from the harmony test, but I do know that when we had genetic counseling she told us not to get one as she has dealt with many parents that had been given the incorrect results and problem had been picked up later in the pregnancy :( she also said that is one of the main reasons it is not available on the NHS as it is not accurate enough!

Hth

It's a screening test not diagnostic, when you get your results it will still give you a risk eg 1:10000 or 1:2 etc.

It's more accurate than current nhs blood test for downs risk plus nuchal scan

Really cookie? Wow. So one of the three trisomys was missed?

We were advised by our genetic counsellor that its extremely accurate (near 100%) and that its used diagnostically in Australia following rigorous studies. I wouldnt hesitate to recommend it.

The nhs are looking to bring it in over the next few years. The reason they havent yet is that there are currently no labs set up in the uk.

I should say our local nhs hospital offers harmony at cost (£270). So they take the blood and send it off to america free of charge which was great for us as nearest private clinic offering it is 150 miles away and would have cost at least double that.

The staff at our hospital were extremely enthusiastic about it as an option for us following our high risk screening result.

cookie I don't think that's correct. It's been signed off and in common use here in the US for 4-5 years and is roundly recommended as more accurate than the other later term testing. There's always the outside chance it may be incorrect (hence why they don't say it's 100%) but I have not yet read anything on message boards etc about getting wrong results in follow up scans.

One of the reasons I suspect it's not available on the NHS is simply the cost and availability.

The labs that process the tests are based within the US, and it's a limited number of places that process the results. As a result, the list price cost is circa $1500-$2000 per test; I know in the UK it's up to about 400-500 pounds, depending on where you have it done.

AFAIK the Harmony test is highly accurate, slightly less so for T13 than for T21 or T18. That said, our first baby had T13 which showed up in a higher risk result on the Harmony test and was confirmed by CVS.

It is available on the NHS, but only through certain teaching hospitAls. I had mine done through uch via great ormond street. Results took a lot longer on nhs tho and they also lost my bloods. Personally, I'd be more likely to go for the panorama test- it detects everything harmony does, but also triploidy. Only available privately though.

I had Harmony with DS who is now 11 months and all the research I did indicated that the chances of a false negative are negligible and the chances of a false positive slightly less so, but still minute. Positive or higher risk results then require amniocentesis for diagnosis.

So that's at odds with what you were told cookie

I've just had the test again as I'm 11 weeks pregnant. I'm currently awaiting the results.

I think it's pretty accurate. There was a thread in anti natal testing of someone who got a false negative and baby had a trisomy. However, I think she had a really unusual result 1:3756 for example. I had the test but after that thread I'd have asked for it to be redone with an 'intermediate result'.

It's definitely the most accurate option unless you want to go for a cvs or amino.

It's incredibly accurate: around 1% false negative and 0.1% false positive. Source: www.ariosadx.com/healthcare-professionals/performance/

tolly our results came in 8 days after blood taken and my blood had to be couriered from our local nhs hospital to london before being flown to san jose. Perhaps you were unlucky? Thats rubbish they lost your blood!

Sorry! Not sure why she told us that then! Apologises!

It's very accurate. We used the panorama, which is a similar concept but has a different algorithm (I've got a degree and a PhD in genetics and so does DH, we spent quite a bit of time in the primary literature .) we chose panorama because it screens for more loci and has better success with lower foetal fraction and it was the only one that didn't require a very long trip to a lab. Nothing wrong with harmony though - I'd have that with no hesitation.

it took a lot of the anxiety of early pregnancy away for me and let us really enjoy the 13 week scan and beyond. I'll be having it again for any subsequent pregnancies.

I think it will end up being available on the NHS. Once they scale it up, reduce the cost per run and compare to money spent on much less accurate testing and its consequences I think it'll be a no brainier. Maybe just for over 35 s at first.

It's an amazing test. Very clever. Both dh and I were really impressed with how it works (and we're pretty au fait with the whole field in general.)

is the tiny chance of false negative that it picks up the mothers DNA or mitochondrial DNA with no mutation? Surely thats the same as CVS anyway? And could you get a false positive if the mother didnt have a genetic condition.

I dont know a huge amount about it but i believe it's a PCR test from a blood sample that somehow separates out the mothers and foetal DNA. What about previous pregnancies? All sounds way more accurate than the current screening anyway.

My friend got a false positive on the CVS dueto mosaicism - does happen.

Hi forago,

It is pcr based - they isolate the DNA and amplify it up, then go from there. They aren't looking at mitochondrial DNA - when they amplify they can do it selectively.
The false positives come from mosaicism. Which is why when it's done practitioners should always stress it's a screening test and all positive results should be confirmed with invasive testing.

The bulk of cell free DNA gets degraded very quickly - I think within a few hours. You can get very rare instances of foetal DNA being found in the maternal circulation years after - I think these are from progenitor cells not cell free DNA.

Thanks all. I thought I knew it was virtually infallible but read s couple of weird posts on other threads so thought I'd see if anyone had any different experiences. Wasn't quite expecting skiptons level of knowledge but very glad of it! Wishing you all safe and healthy pregnancies. X

way, way more accurate than the previous risk given from nuchal scan, blood tests and soft markers, then I'd say. Basically if they find DNA with one if the mutations tested for it can only have come from the foetus then or, in very rare cases, from the placenta and not the foetus (mosaicism) - but CVS can also pick this up as a false positive so I think an amnio is the only way to rule it out (DNA from the umbilical fluid which pretty much has to come from the foetus?). They seem to know if this is indicated though (mixture of DNA with and without the mutation I guess) and would presumably recommend an amnio then.

anyway more or less as accurate as CVS it sounds to me.

It's 99.1% accurate, right? So that's almost 1 in 100 that it will fail for.

I'm getting it done tomorrow afternoon as it happens- well actually the Panorama- purely because the turnaround time is 3 days quicker for some reason. I didnt even ask why, but it was the primary reason i chose it over Harmony. My consultant said Harmony was much better for multiples or IVF- neither of which applied to us- so i chose Panorama on the basis that it was results in 7 days, as opposed to 10 with Harmony (I'm in Dublin, might be quicker if you're in London, i dont know)

As mentioned, infinitely more accurate that the triple serum Nuchal test or even nuchal measurement- it's a no brainer for anyone who's worried, as if you are Low Risk you can literally put it aside for the remainder of your pregnancy. If youre high risk? Well that's a bridge to be crossed, etc.

I had "bad" results from the 12 week scan and opted for amnio, due to gestation I ended up with a CVS.
Having been to hell and back, I personally think, if you get "bad" results, just go straight to cvs/amnio. The chances are that if harmony comes back high risk you'll end up being offered and probably taking this route anyway. And when you're in that situation, that extra wait for the harmony results adds a relatively long time to that hellish period, and I don't recommend that to anybody.