Ovulation Predictor Tests: Frequently Asked Questions

If used correctly, ovulation tests are excellent predictors of ovulation. However, in order to detect the LH surge with accuracy, directions must be followed exactly. The most common mistake made with OPKs is generalizing the methods of pregnancy testing to ovulation testing - which leads to errors in use and in the interpretation of results. To get the most out of ovulation testing, read our Ovulation Test FAQ.

Ovulation Test FAQ

Q: How do ovulation tests work?

Ovulation tests detect luteinizing hormone (LH). Just prior to ovulation, women experience a brief surge in luteinizing hormone. Ovulation predictor kits help you pinpoint this surge and anticipate ovulation - your most fertile period in your cycle. Luteinizing hormone, in elevated amounts, is actually the hormone that causes you to ovulate (when the eggs bursts from the ovarian follicle), so that is why lh tests are so effective in anticipating your most fertile time.

Q: How do I interpret results? The same as pregnancy tests?

Ovulation tests function differently than hCG pregnancy tests. A positive result (indicating an LH Surge) is indicated by a test band that is of equal or greater intensity (equal or darker) than the control band. A negative result for the LH Surge is indicated when the test band is of lesser intensity (lighter) than the control band or cannot be seen. Click here to see diagrams of test results.

Q: What is the best time of day to take the ovulation test?

Unlike pregnancy tests, morning (first morning urine) is not the best time to collect samples for ovulation tests, as LH is synthesized in your body early in the morning and will not appear in your urine until the afternoon. The ideal time to test is in the afternoon, around 2pm, though testing may safely take place from 10am to early evening.

Q: Should I take the test the same time every day?

Yes, be sure to test at the same time each day. Also, reduce your liquid intake around 2 hours before testing as a diluted liquid sample can prevent or hinder LH detection.

Q: When should I beginning testing with the ovulation predictor kit?

To determine when to start testing, you must first determine the length of your menstrual cycle. The length of the menstrual cycle is the number of days from the first day of menstrual bleeding to the day before bleeding begins on the next period. Determine the usual length of the menstrual cycle over the last few months. Then, refer to the Cycle Chart to determine on which day of the menstrual cycle to begin testing. Click Here determine when to begin testing?

Q: How long after my LH surge will ovulation take place?

Generally, ovulation will take place 12-48 hours after the LH surge is first detected (using afternoon urine samples), though 36 hours is considered to be the average length of time following the LH surge.

Q: When I get a positive on an ovulation test, when is the best time to have intercourse?

To increase the chance of conception, it is best to have intercourse the day of the LH surge as well as following three days after.

Q: Does the appearance of faint 'test band' indicate an LH surge?

A faint line (or a faint positive test band) does not indicate a positive result for an LH surge. While the presence of a faint line on a pregnancy test may indicate a positive result, a faint line on an OPK is always negative.

Q: Does taking my basal body temperature tell me the same thing as an OPK?

Basal Body Temperature only tells of your LH surge after it is over. That is why the BBT method cannot predict the LH surge. Ovulation tests will tell you - with pinpoint accuracy - when your chances for conception are greatest.

Q: Can OPKs be used as contraception devices?

Ovulation tests are designed to help facilitate pregnancy. They are not recommended for contraception.

Q: Can clomid interfere with test results or cause false positives?

Clomid may cause false positives if you test for ovulation too early in your cycle. Please consult with your doctor about how to use OPKs in conjunction with Clomid - or other fertility and prescription drugs.

Q: Does a light test line and a dark control line indicate a positive result?

Ovulation tests are unlike pregnancy tests - especially when it comes to interpreting results. The results are only positive if the test line is equal to or darker than the control line.

Q: I had a positive result yesterday and today. Does that mean there is something wrong?

Such results may indicate that your the tests detected the LH Surge on the way up and again on the way down.

Q: What if I experience a BBT thermal shift but the ovulation tests failed to detect my LH Surge?

It is possible to miss the surge. If you have a test line that is fairly dark one day then very light the next, you may have missed the actual surge. If your thermal shift occurs, you probably ovulated. It may be a good idea to test twice a day when you feel that you are close to ovulating. Another possibility is that you didn't hold your urine long enough (resulting in a diluted sample).

See Also:
> How do OPKs work?
> How do I interpret ovulation test results?