Opk - fermometer neg but flashing smiley on clear blue

[Bells3032]

Had my coil out 6 weeks ago after 17 years on various Bc Inc 5 years on merina.

Been using fermometer strips (bought from amazon) pretty much every day but not a single positive. So started trying cb a week ago and today finally got a flashing smiley.

Tried to fermometer strip with the same pee and nada.

Which is correct?

The CB is probably correct because it measures your baseline LH and then when it detects a 5x increase, it gives you the smiley. In contrast, the strips have a certain threshold above which they indicate positive. But LH can vary a lot from woman to woman. It sounds like you have low LH and the strips cannot detect your surge. But if the CB said you have a surge, you can trust it, because it knows your baseline. Does that make sense?

Oooh I didnt realised that cb had memory I did notice you had to reset it each month so that makes sense

Does having low lh mean I have a problem

Not necessarily, if you are getting your periods regularly and you ovulate.
Best way to confirm ovulation is to track your basal body temperature. CB and strips can only tell you there is an LH surge, but they can't tell you if this surge will lead to the actual release of an egg.
Low LH levels have been associated with malnutrition and stress. I would track a few cycles before getting concerned though, there are many women who can not detect their surge with strips.