I've used PTFE dental floss for decades, and recently diagnosed with a thyroid condition. I wonder if there could be a connection. This test will at least give me an idea of my blood levels of PFAS.
You are perfectly fine with PTFE dental floss - it has no reactive PFAS components in it.
PTFE, the material, does not contain PFAS in bulk form.
That's the end.
Floss, as a product, could contain any number of compounds related to the manufacturing, packaging and coating.
I went with Grin because they said it's PFAS free. Best I could do.