NIPT question

[Motheratlast123]

Please can you help me understand if NIPT can give a false negative? I am worried that even a negative result does not rule out Downs but am struggling to find any data on this.

I would really appreciate any help.

The chances are incredibly slim!

I've had NIPT with my third pregnancy with my son (negative) and about to have with my current pregnancy.

Just be aware that the testing usually only looks for certain genetic abnormalities. My now 4 year old son has a chromosome abnormality that was not tested for and is disabled so it's not a guarantee of health and wellness.

I'm doing it this time due to my age and the fact that other more common chromosome abnormalities are more likely with older mums (I'm 39)

I think the nipt goes up to a 10,000 in 1 chance (or it did when I had mine in 2016) so yes obviously someone can be that 1 chance. It is the best result you are going to get without an ammio and even then like a PP they don't test for everything.

I’m a midwife and have seen it happen a couple of times where the NIPT gives a low risk result and a baby has been born with Down Syndrome. It’s uncommon but does happen. It’s important to remember that the NIPT is not a diagnostic test, it’s a screening tool only so it’s not going to be 100%

Thanks so much for your help. Really appreciate it.

Vikki7, I appreciate you mentioning the limitations of the NIPT and am grateful you shared a personal story.
Ohhhhhbiscuits - that is a good point that amnio does not test for everything either. Thank you.
Afterglow87- thank you for letting me know that there are false negatives. I had never heard of one but have limited knowledge of numbers so appreciate your insight.

Are there certain conditions that must be met for an amniocentesis? I also could not find any NICE guidelines on this aspect which clearly define when it is necessary.

There is no test that is 100% accurate. NIPT is more accurate than combined screening, which is more accurate than quad screening etc.

Even an amnio isn't 100% guaranteed to give a result, and can only test for so many things. It's most accurate but comes with a risk as its an invasive test. To most if the NIPT or combined gives a low chance result (e.g. 1 in 4000), it's not worth a procedure that has a 1 in 200 chance of miscarriage. I'm not sure many doctors would even be willing to perform it.

Down's is also not the only disability, the vast majority aren't able to be tested for. It also doesn't discount other issues that can unfortunatley happen e.g. baby's brain getting deprived of oxygen during birth. Unfortunately no matter what you do you can't be guaranteed a healthy baby.

I appreciate your replies and help with this. I will post about amniocentesis separately to understand this part better as currently deciding.

You can, however amniocentesis is only offered in certain situations. You likely can't request on NHS if you had a low risk NIPT result unless you meet other criteria as outlined below. Even privately you would likely struggle to find someone willing to perform the procedure.

https://www.nhs.uk/conditions/amniocentesis/#:~:text=It's%20important%20to%20remember%20that,help%20you%20make%20a%20decision.