OADCB are you using a CBFM or a Clearblue Digital ovulation predictor?
You can tell a little bit from looking at the lines...
If you are using a CBFM I'll explain, but comment on the CB digital OPKs.
How the CBFM works:
The stick uses two assays, one for oestradiol and one for leuteinising hormone (LH). The assay for oestradiol is negative and therefore the line becomes fainter the more oestradiol is in your system. The LH assay is a positive one and therefore as LH levels rise, the line becomes darker.
When CBFM first asks you to POAS it measures your baseline levels. This should be when you have low oestradiol and low LH in your system. It "remembers" the intensity of the colours on the stick that it measures and compares all subsequent readings to this. At this early stage, the line closest to the wick on which you pee should be very faint or non-existent. This is the LH line. LH levels should be low at this early stage.
At the same time, the line furthest away from the end on which you pee should be quite dark. This will show that you have a low level of oestradiol in your system.
As your cycle progresses, oestradiol levels begin to rise. The line furthest away from the end on which you pee will become fainter. When the CBFM detects the intensity of colour has reduced (indicating a peak in oestradiol) a reading of "high" fertility is displayed by the monitor.
The peak in oestradiol levels trigger a rise and peak in LH levels. LH is the hormone that triggers ovulation. Over the next 1 - 5 days the line furthest away from the end you pee (oestradiol) will begin to darken as hormone levels reduce. The line closest to the end on which you pee will also begin to darken as LH surges. When the monitor detects this it is triggered to display peak. Ovulation follows 24 - 48 hours after the initial peak in LH.
So in summary, if you put the stick in front of you with the end on which you pee to the left then:
Start of cycle: left line faint, right line dark
Oestradiol peak: left line faint, right line faint
LH peak (immediately before ovulation): left line dark, right line dark
Aftr ovulation: left line faint, right line dark
HTH
The problem with the CBFM is that as it conares to baseline levels, it won't necessarily detect a peak in LH if your baseline LH levels are high (Which can be seen in some conditions such as PCOS).
The other thing is that some women have a very short LH surge, and the surge often occurs in the afternoon. It could be that the CBFM is missing it.
Obviously, if you are using the digital tests then ignore this post!