Today I am 15 DPO. I noticed that on 13 DPO my test was a tad darker than at 14 DPO. Should I be concerned? Shouldn't it get darker? Both taken at the same time of day.

***Didn't test today as I told myself I am spending too much money on testing. I have a blood draw on Thursday am. My levels yesterday were 109.3.

***Here is my test from am and pm yesterday of a different brand, an early result equate test.