How Ovulation Tests Work

Home ovulation tests help determine the best time to attempt conception. Tests detect the luteinising hormone (LH) which is responsible for ovulation with a 99 percent accuracy rate. . LH levels surge 24-36 hours before ovulation. Home ovulation tests detect the LH surge via chemically analyzing a urine sample to detect the amount of LH present.

There are two types of ovulation tests currently on the market. Both formats have been shown to be just as reliable.
To use test strips, you fill a sterile container with urine and dip the strip into the container for a predetermined number of seconds. Midstream tests are held in the urine stream like a home pregnancy test.

Response time for most home ovulation testing kits is about five minutes. At the end of five minutes, a control color band will indicate whether the test is working or not. The control band also supplies a color and intensity baseline that is helpful in interpreting the test band result. The test band indicates whether you are ovulating or not.

A test band indicating an LH surge is usually equal to or darker in color than the control band. A test band indicating no LH surge has occurred will be lighter than the control band or not present at all. As there is always some amount of LH present in the system, a light test band does not indicate a positive result.

The LH surge at the time of ovulation is woefully brief. To detect the surge, it is necessary to test at the right time of month in addition to the right time of day. Most testing instructions indicate the best time to test is at 11AM, 3PM, 5PM and 10PM. To increase your opportunity of catching the surge it may be in your interest to test twice a day, once in the morning and once in the evening. It is recommended that you decrease fluid intake two hours before testing as too much liquid can dilute the amount of LH in the urine.

Ovulation tests using blood as an LH surge indicator will gather a positive result four to five hours before a urine test. Some women find that best samples are gathered after noon time. Once you have noted the LH surge, conception is most probable one to three days after this surge. This period is the peak fertility time of your cycle.

Before using any ovulation tests, read the instruction page carefully. Tests should always be stored unopened at room temperature.
Finally, some medications such as menotropins and danazol may skew the results of an ovulation test. The fertility drug, Clomid, may cause false positive if you test too early during your cycle. If you have recently stopped taking the pill, your cycle may not have stabilized. It may be advisable to wait through two menstrual cycles before using ovulation tests to monitor LH levels.

Ovulation tests are an excellent resource in determining when ovulation is about to occur. When these tests are used in tandem with other fertility predictors such as BBT; cervical mucus and cervical positioning, you will begin to see the pattern of your menstrual cycle. It is in understanding the intricacies of your body and its cyclic shifts that will ultimately aid you in achieving conception.

Good luck!

Leila Pereira
Leila Pereira
I work in occupational therapy and occupational science. I specialize in early intervention pediatrics for children from birth to three years old; with an emphasis on children with autism. My goals are to support the achievement of developmental milestones in your child while collaborating with caregivers & parents; including play skill development, education, leisure, rest and sleep, feeding, nutrition and social participation. Licensed by the California Board of Occupational Therapy

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