OPK...

APC2011

how acuate are the OPK?  

Dr.Loretta

Define "how accurate". As in, how closely do they predict ovulation, what if you never catch a surge, what should the pattern look like leading up to a surge, etc.

Some people have OPKs that get progressively darker, then eventually go positive. So even if they don't catch the peak surge, they have a good idea when they have a +OPK. Some go from stark white to positive, and may need to take more than one OPK a day to catch their surge. Some people c

an test with FMU no problem, while others have better experiences testing mid afternoon.

Some people typically see a +OPK the day before they ovulate, some the day of, some 2 days before, and some can be all over the map from cycle to cycle.

And some people (more rarely) may have a surge but fail to ovulate.

IMO they should be used with some other fertility awareness method to cover your bases. They can predict when you're likely to ovulate, but charting temps for example can confirm ovulation.