NIPT fetal fraction

[Starlight11111]

Hi all, anyone with any experience of NIPT results with 3% fetal fraction? Not sure whether this % could affect accuracy of the screening results / sex. Thank you xx

So the fetal fraction should be over 4pc. How far along were you when getting the NIPT done? The NIPT subreddit is brilliant and loads of people have been in a similar situation.

I don't remember the exact percentages but our first NIPT failed for low fetal fraction. We'd had it done right at the earliest point, so we just had it redone two weeks later and it came back fine that time (with both genetic results and sex).

So Ultrasound Direct say the fetal fraction needs to be above 1.5%?

It depends which test you took, some require higher ff than others. A nurse told me Harmony has a high failure rate due to requiring larger ff, some newer ones on the market are lower. I just had a prenatalsafe test result back which was 3% minimum iirc

Thanks all. The test was the illumina one and having researched more I think their failure rate is much lower ~1.5%. I was only 10+5 (confirmed by scan before test) at the point of the blood draw. Appreciate your experiences xxxxx

Hi @Starlight11111 what was the outcome of this? My results came back but with 4.7% fraction I’m wondering if they’re actually reliable or not 😔

@Fetalfractionquestion I'm not due until September so hard to say for now. From what I've read labs can either do the test or they can't, in which case results will be inconclusive and need to be retested. I did a lot of research and found some of the newer tests are fine with as low as 1.5%.

I opted for the NHS screening tests and all came back low risk which matched NIPT. Xx

Interesting, thanks for getting back to me @Starlight11111! Did you opt to find out gender, too? Does your NIPT match NHS with that too? We have been told girl but wondering if we should hold off telling people anything (gender, the abnormality results etc) until we have had our 20 week scan. It’s hard, I want to buy things and prepare but also worried!

@Fetalfractionquestion we did and we haven't had that confirmed yet but will with a scan in ~2 weeks. It's so rare for gender to be incorrect with NIPT. I have told people what the NIPT gender said and also that we will be getting it confirmed with scan before buying anything gender specific!

I know the accuracy rates are high, I just keep reading things about false positives for those with lower fetal fraction. Maybe I’m getting myself too worked up over nothing. Good idea though @Starlight11111 we might have to adopt similar! I love NIPT but somehow I feel like it’s made me more anxious overall 🥲