Posted 9/30/2019 10:59 AM (GMT -7)
I'm writing a blog post about my experience with C. diff (combined with UC), and I want to make sure I get my story right...but the more I try to understand what happened to me, the more confused I get. My confusion centers around the science of C. diff lab testing. I'm wondering if anyone out there is a science-y person who might be able to explain the NAAT test to me, or who might point me to some layperson-friendly resources that can explain it simply.
I was tested for C. diff 3 times in 2016, using the NAAT test. The first two results came back negative; the third was positive. However, I was convinced at the time (and have been convinced ever since) that I did have C. diff that whole time, and that those first two tests were false negatives. The story in my head has been, essentially, that if I hadn't gotten that third test, I would have died--I was very gravely ill in the hospital by the time we finally learned I had C. diff. Relatedly, my internal story has been that those first two false negatives endangered my life.
My conviction that the first two test results were false comes from the way my symptoms changed when the C. diff finally went away. The C. diff happened during a UC flare, and after the C. diff was treated, I was left with just the flare. Being able to witness which symptoms disappeared with the C. diff, and which symptoms remained with the flare, made me able to look back and recognize when the C. diff had first set in.
At least, that's the story I've had in my head for years. But now I'm doing some research, and everything I read about the NAAT test says that it's really accurate. This is the confusing thing. I've always thought that false negatives were common with C. diff tests, because that is true of other forms of testing, so it made sense that my first two results were wrong. But I'm not finding statements that the NAAT turns up many false negatives--so maybe my inner story is wrong, and I really didn't have C. diff till much later than I thought!?
So here's my main question: Does the NAAT turn up false negatives, and how likely is it that my first two results really were negative in 2016? If they were very likely accurate results, I'll have to revise a lot of my thinking!
So far, here are the articles I've read... I can't decipher any of them, though, despite having a master's of science degree myself! Help would be greatly appreciated.
https://www.aacc.org/publications/cln/cln-stat/2018/april/19/naat-on-the-rise-in-detecting-c,-d-,-difficile-infection
https://jcm.asm.org/content/56/3/e01316-17
https://www.medscape.com/viewarticle/815147