As far as I know PAPP-A on it's own is not necessarily a prognostic marker. It is the ratio between the f-hgc (free beta) and the PAPP-A that has contributed to your 1:170 results.
That's the whole thing with the first trimester screen. No single factor is a strong indicator of anything. It is the combination of factors...the ratio between the two hormones combined with age and soft markers. You can double check with your OB (and I would encourage you to do so as I am not a medical professional), but I don't think you can take any one single number of marker on it's own as an indication of anything. Also, it is extremely important to remember that none of these tests are diagnostic. The only reason for these tests is to help you determine whether you would like diagnostic testing which is invasive and carries certain risks that these tests do not.
All the best to you.
Thank you for your kind and specific response.
But, as a single prognostic marker, what is the specificity of PAPP-A? Our result is extremely low - so low as it is seen in less than 2% of the normal fetuses...
Thank you for your kind and specific response.
But, as a single prognostic marker, what is the specificity of PAPP-A? Our result is extremely low - so low as it is seen in less than 2% of the normal fetuses...
Hi there. These tests are confusing aren't they. At my first trimester screen, I had a result of 1:13 for DS, and my son is completely typical.
Here is how the blood test works (or at least how my perinatologist explained it to me).
What they are looking for is not the actual number itself, but the ratio between free beta and Papp-A. The greater the ratio, the higher the odds. This is combined with your age, and then the soft markers they look for such as a thicker then average nuchal fold, shorter then average femur bone, etc. (surprisingly, they don't factor in presence or absence of a nasal bone in the equation).
This test is absolutely not diagnostic. It calculates your odds, and that is it. The entire purpose of it is to help you determine whether or not you would like to have more invasive testing like amnio done which is diagnostic.
If they did the blood alone, or just the soft markers alone (such as NT), the results in terms of your odds would be much different. None on their own is a good indicator.
As I said, my results came back 1:13 and I did opt for amnio. My son is now 2 years old and completely and totally typical. I personally had a good experience with the amnio, and the peace of mind I got finding out all was well was really important for me.
1:170 are excellent odds. You have less then a 1% chance. I know it's scary, but once you put that number into perspective, it might help you to relax a bit. All the best to you.