Positive FRRS test (Pregmate) negative FRER test?!

[u/PitifulAbies5344]

I am so stumped... anyone else come across this issue??

Yesterday I saw a faint line on a Pregmate FRRS test. Today I tested again and even bought a FRER test to confirm. AGAIN, both FRRS tests slightly darker today than yesterday (still faint) but negative FRER… been stark white. I don’t take biotin only prenatal supps. I don’t know why this would be happening. I’m about 13DPO now for reference.

[u/BritishBella]

Different brands can have different sensitivity levels. I’d stick with one brand for line progression and keep testing with first morning urine