How do Ovulation Tests Work?

Since we are in the business of testing, we often get asked this question - how do ovulation tests work? Of course this is an important question, and important to understand.

Ovulation tests work by detecting concentrations of Luteinizing Hormone (LH), a hormone that increases as ovulation approaches. Just prior to ovulation, this hormone peaks, in a process called ovulation surge. Using tests allows you to watch as it peaks, indicating that ovulation is about to occur.

Ovulation tests depend on antibodies - Y-shaped proteins that our immune system normally deploys in defense against invading viruses, bacteria or anything else foreign to the body.

Every antibody binds tightly and with high specificity only to certain foreign molecules, or antigens, and this specificity is what guides the immune defenses.

Ovulation tests contain special antibodies. When a urine sample is applied some of these antibodies will bind with the LH if present. These antibodies, along with unbound ones, flow up the test.

At the test region of the ovulation test, the bound antibodies bind with other antibodies that are immobilized on the test and form a colored line, showing a detection of LH.

The rest of the unbound antibodies continue to flow up the test, and bind at the control line in the same manner, forming another colored line. The control line serves to show that the antibodies flow up the test correctly and the ovulation test is working.

In this manner, these tests visually indicate whether LH is present in the urine, and qualitatively tell you how much. Testing daily with these will allow you to track your cycle, and determine the best time to try to conceive.