from what I understand it tests for the Luteinizing hormone surge. Your temperature can be affected by MANY things so don't always go by that, best thing I believe is to chart your CM instead.
Here is more on the temp stuff:
Basal (resting) body temperatures are necessary when using temperature charting to identify the increased levels of progesterone that occur with ovulation and in the second half of the menstrual cycle. It is for this reason that it is important that you take your temperature before getting out of bed and before undertaking any activity including talking or eating or drinking. If something does need to be done, e.g. going to the toilet, move slowly and gently and take the temperature on returning to bed as soon as possible.
At least four hours sleep is required for your body to have reached its at-rest stage so if your night was short or disturbed note it down.
Read your temperature at approximately the same time every day. The basal temperature is much higher later in the day and lower earlier, regardless of how much sleep you have had.
If you rise earlier than usual, adjust your temperature up by 0.2° F (0.1° C) for each hour before recording it.
If you rise later than usual, adjust your temperature down by 0.2° F (0.1° C) for each hour before recording it.
Always take your temperature under all circumstances. Just make sure that you make a note what any unusual circumstances were.
Other conditions you may need to record that can affect your temperature are:
* Ill health
* Stress
* Hangovers
* Medication and Drugs
* Air travel across time zones
* Extreme temperature changes (such as leaving your electric blanket on all night and waking up in a sweat)
Here is an excerpt from a book:
In the majority of cases it appears that ovulation occurs about 30 hours after the LH surge takes place in the blood. The LH does not show up in the urine for another 4 to 6 hours, so even if you detect the surge just as it enters the urine you are still only about 24 hours from ovulation in many cases.
making sure not to miss my surge. It was negative (which was the day of the temp dip) I did get a positive yesterday around 2pm and it was positive several times i tested until around 11am today the 25th so why am I getting a positive OPK after my temp dip and on the days of my temp rise ?
