Combined Screening - help understanding results

[AnnieStar12]

Can anyone help me understand my NHS combined screening results for T21 risk (my risk for T18 and T13 have come back in the many thousands so not concerned with those).

My results say the following:

Background risk (based on age, 41): 1/57
Adjusted risk (based on age, scan & bloods): 1/145
Adjusted risk at term: 1/207

The written commentary says my risk is "low" because it is less than 1/150.

I am really confused why I have two adjusted risk levels, and am a bit concerned given that the NHS use 1/150 as the cut off for whether you are considered high risk or low risk and both my results are close to that cut off, and one being on the high-risk side. I'm struggling to contact the hospital to ask what it all means.

Does anyone understand why I've been given two adjusted risk levels? Is one my risk level right now and one my risk level if I make it to full-term?! So confused!

I have already done a NIPT test, but the fetal fraction was only 3% and I've been told that makes the results much less reliable, even though it did come back as low-risk.

I'm not an expert so could be wrong. But I believe it's saying the main risk factor is your age. So age alone makes you high risk, but the measurements and blood work are so 'good' it actually lowers your risk.

Hi, I've never seen it broken down like that before (in my area it just comes back as 1 risk ratio).

My interpretation of this would be that for your age, you could anticipate a 1/57 chance of a baby born with T21. However, based on scan and bloods, the risk for this actual pregnancy is 1/145.

I would assume as the test takes into account gestation, that the final 'adjusted risk' at term is your actual final risk assessment. So, of babies who make it to term, with your age and bloods/scans, they'd only expect 1/207 to have T21.

I would take this to mean your risk is low. However, perceptions of risk are very individual, and some people are more risk tolerant / risk aversive than others. If you are feeling like that risk is too much for you personally, you could redo the NIPT (as the NHS have classed you low risk I assume they would not offer any more testing even if you asked).

Someone else may have more experience with this though and provide a better answer!

"I would assume as the test takes into account gestation, that the final 'adjusted risk' at term is your actual final risk assessment. So, of babies who make it to term, with your age and bloods/scans, they'd only expect 1/207 to have T21"

Yeah, you might be right I was wondering if this is what it means too, but that is such a big difference in risk level between 12 and 40 weeks?! So weird, I almost wish they didn't give me so much detailed breakdown. There is loads more too which is sooo complicated.

I had my results back. I called the screening line and they said due to my age (43)

I started as 1/50 - age before any blood is taken
nt scan was 1.6mm so made it go up
my HCG level was good made it go up again
I have low Papp a so made the score lower but ended up in 1/253 chance of having a downs which is still really low risk

my other results were 1/3000

Does that make sense.

I just spoke to the screening midwife who was really helpful and said my results show all the raw data which isn't very helpful, but the main result that matters is the end result which is 1/207 which is a low-risk result as it's about 0.5% chance. I would have preferred a lower risk result for peace of mind but at least I understand what's going on now!

That’s exactly how I was that initial letter explained nothing.

@Rosyposy26 The lady I spoke to hadn’t realised that patients get all those results sent to us via the app! I don’t think it’s helpful having that much detail, just the final number would have been better. But she was great, spent almost 40 mins on the phone explaining it all and helping me understand what it means. Glad you got a low risk too. It’s scary being pregnant over 40!

@AnnieStar12 it is yes so much scare stories but I feel
healthier now than in my 20s