Harmony test can anyone who's had one please advise!

[Everythingstaken]

I trying to decide whether the Harmony tests results will give me the clarity I need. My understanding is that it is most accurate for DS but less so for T18 & T13. I am trying to make a decision under very tight timescales so please forgive me if this information is available elsewhere but From what I have read on this forum the results are not definitive like an amino. What I am trying to understand is what does a high risk result appear as and what does a low risk result look like? I think my worry is that I still won't feel able to relax following a harmony result, I have a high risk of 1:15 high HCG low PAP A, neuchal of 1.5 so very much indicative of DS (except the neuchal). I am so stressed and worried I can't seem to get my head round this which at 40 I am ashamed to admit.

Hallo. I hope one of the more informed posters will be about soon. I've had the harmony test in 2 pregnancies, and as far as I can recall (only had it a few weeks ago, my brain is zapped), if it's negative it gives you a probability of not having ds, not a definite yes/no. However, the chance of that negative result being incorrect is, iirc, 1/10,000. So basically it is yes/no to all extents and purposes.

As far as I know harmony is slightly less accurate for t18 and t13. However, we have been advised to have one after loosing out dd2 to t18.

They are not diagnostic but I have heard they are used diagnostically in some countries for a negative (as in the 1:10000 is a negative)

It won't however give you a definite positive. If you come out high risk (I imagine quite likely with the 1:15 risk factor you have) then you would need a diagnostic cvs or amnio.

I understand the need to know as soon as possible. Is there another reason that your time frame is so tight?

I know it is a different diagnosis but dd2 was diagnosed at 22 weeks with Edwards. We decided on a tfmr. I am more than happy to answer any questions about amnios, diagnosis and tfmr if that would help at all.

I'm sorry you're in this worrying situation

www.wolfson.qmul.ac.uk/service-1/antenatal-screening/screening-tests/calculating-the-risk-of-down-s-syndrome There is some detailed info here particularly re the HCG, PAP A results and how the risks are calculated

Re timescales - the Harmony test will take approx. 2 weeks www.fetalmedicine.com/harmony-test

I think if you can have the Harmony at 10-11 weeks then waiting the 2 weeks for results is okay

If you are further along & the harmony result suggests a high risk of T21, you are looking at adding another week or two to get a CVS done and the results in

If it helps the high hcg and low papp a are not usually pointers for t13 or t18 so a harmony probably would be fairly accurate

I had harmony at 10 weeks for this pregnancy (20w now). The results were back in one week. You get a risk estimate for t13, t18, and t21. The test is very accurate for all three but because the first two are so rare (so they've been able to do fewer tests) they cannot claim the same accuracy rating as for t21. However the technique used is identical for all three and for the sex chromosome checks (e.g. Turner's), so my opinion as a scientist in a related discipline is that eventually given sufficient numbers tested, the accuracy claims for t13 and t18 will be similar to t21. I think it's well worth doing if you don't want to risk an amnio. 1 in 15 is still 14 in 15 odds that your baby is fine and the nt screen is well known for a high false positive rate.

Thank you so much for taking the time to reply. It is such a worrying situation and I just want to feel confident with the results from whichever option I take. Your replies have helped enormously. Thank you again.