How to Read an Ovulation Test: Faint Lines & Test Types

Knowing when you ovulate in your cycle is useful for many reasons but especially when trying to conceive. After all, ovulation preparation is short, lasting around 24-36 hours. When you’re trying to conceive, it’s critical not to miss the days leading up to ovulation and that day of ovulation itself (collectively known as your fertile window) so that you do not miss your best opportunity to conceive.

Knowing the day you will ovulate maximizes your chances of getting pregnant and gives you more control over the process of conception. Ovulation tests or ovulation strips can help take the guesswork out of knowing when you ovulate, but they need to be used accurately to get the best results. In this post, we’ll go over how ovulation tests work, when to take them, how to read results, and other tips for tracking fertility naturally. 

Wondering how to test for ovulation? Our guide will explain how to interpret your test kit and confirm that the test results are accurate. Let’s go! 

How Do Ovulation Tests Work?

Ovulation test kits, or ovulation predictor kits (OPKs), determine when you are ovulating by measuring the hormone levels in your urine. Ovulation is tightly controlled by luteinizing hormone (LH). LH levels remain steady throughout most of the menstrual cycle but surge dramatically 24 to 36 hours before ovulation. After ovulation, they return to basal levels.

You can identify when you are about to ovulate by pinpointing your LH surge. This is how OPKs work to predict ovulation. They don’t confirm that an egg was released. Once the ovary releases an egg, the egg has only 12-24 hours of lifespan to be fertilized by sperm. These 12-24 hours are your most fertile time of the menstrual cycle and the best time to have intercourse to maximize your chance of conceiving. 

Since sperm can survive up to five days in the woman’s reproductive tract, your fertile window consists of the five days leading up to ovulation and the day of ovulation itself. This is why experts recommend having sex before or at the surge. You are most likely to get pregnant if you have sex in the two days prior to ovulation or on the day of ovulation. 

When to Test for Ovulation

Since ovulation test strips can help you predict when you are most likely to be fertile, you can take the test when approaching ovulation. Ovulation usually takes place in the middle of the menstrual cycle, give or take a few days, so your most fertile days of the month are 1 to 2 days before and after the ovaries release an egg.

A regular menstrual cycle makes it easier to predict ovulation. Because if you have a 28 day cycle, you will most likely ovulate on or around day 14, meaning you should start testing around day 10 or 11. It’s a good idea to continue testing until you see an LH surge, especially until you know your cycle better.

However, if you have a short cycle, you can consider that you will most probably ovulate within 4 days of your cycle’s midpoint. You should start testing for ovulation 4 to 6 days before the middle of your cycle.

When is the best time to take an ovulation test? Although technically you can take the LH ovulation test at any time of day, the best time to test for ovulation is early afternoon because LH levels are generally highest during this period. Testing around noon can boost your chances of getting a positive ovulation test strip. Individual differences in LH peaks can mean some women peak at different times. One thing is true no matter when you take the test, limit fluid intake for at least 2 hours before the test so you get the most concentrated results.

It’s also important to understand that not all LH surges are over within a day or two. There are 2 types of LH surges: rapid LH surge and gradual LH surge. A study revealed that about 43% of women experience rapid surges that are over within a day, and 57.1% of women have gradual surges that are over 2-6 days. For some women, testing once a day is sufficient, but for others (such as those with short surges or irregular cycles), testing twice a day can help ensure you don’t miss your peak. 

When to Take Ovulation Test After Period

The standard advice for taking an ovulation test is to start around day 10 of your cycle (if your cycle is 28 days long). Remember that cycle day 1 is the first day of flow, and you begin counting from that day. For the average 28-day cycle, you should start testing about halfway through, on days 9-14. For shorter cycles, like 26 days, testing should occur between days 7-12; for longer cycles, like 35 days, testing should occur between days 16-21.

If your cycles vary, it can be hard to know when to begin testing. It can be helpful to track your cycles for several months to identify a pattern, or use the shortest recent cycle as a conservative starting point. Keep in mind that with variable cycles, you may need to test more frequently and over a larger window to capture ovulation. 

How to Use Ovulation Strips

An ovulation kit uses test strips dipped in urine to detect the LH surge before the release of an egg. Like a pregnancy test, the OPK consists of a test wand inserted into the stream of urine.

The step-by-step instructions for how to use ovulation strips:

1. Unwrap the test strip.

2. Collect a urine sample in a cup or insert the stick directly into the stream of urine.

3. Dip the strip for the time specified in the instructions.

4. Lay the strip flat and wait 5 minutes to read the results.

5. Dispose of the test strip (for digital tests, eject the test strip from the digital holder).

Read and follow the instructions for your kit carefully, including expiration dates and storage tips. Avoid excessive hydration by limiting fluids for at least two hours before you plan to test and avoid urinating during that time. Although many tests recommend morning testing because it’s the easiest to manage, find a time that works for you and your cycle and stay consistent by testing at the same time every day.

Paper Strips vs Digital Tests

How to Read Ovulation Test Results

Positive Ovulation Test Strip

When inserted into the urine, a control line will appear on your ovulation test. If the control line does not appear, you should take a second test using a new strip. 

When LH exceeds a certain threshold, a second line that is as dark as or darker than the control line will appear to indicate that you will ovulate in 24 to 36 hours. On digital tests, the display will indicate “peak” or a smiley face to show that your body is preparing to ovulate.

Generally speaking, you should aim to have sex with your partner at least once every other day during your fertile window. That means that once you get a positive test result, it’s time to try to conceive. Your chances of conceiving are at their highest on the following days:

• 2 days before ovulation

• 1 day before ovulation

• The day of ovulation

• 1 day after ovulation

The LH surge is a rather sharp change of the hormone and usually lasts very briefly. Variability is high, and differences can occur from woman to woman and cycle to cycle. Given these variabilities, it can be easy to miss your peak. Some women may see a longer peak than others though and should keep testing throughout their fertile window. 

A line that is lighter than the control line or not present indicates that LH is too low to suggest approaching ovulation. If you begin testing several days before ovulation, you should be able to see the lines get progressively darker as you approach your LH surge. 

Reading Lines: Faint, Negative, and “High” (Non-Peak) Results

Reading the results of ovulation test strips can be tricky. Some people have trouble reading the test results and the second line is often difficult to interpret. It can be difficult to determine whether the second line is dark enough to be considered a positive result.

Faint lines can be particularly challenging for test results. If the faint line that appears is the control line and the test line is absent, your test has not detected an LH surge and you are not ovulating. If the faint line appears and the control line is absent, your test has not worked, and you should take a new one. If you begin testing several days before ovulation, you should be able to see the lines get progressively darker as you approach your LH peak - keep testing!

If your result is always negative, there are several possible explanations. You may be testing too early or too late and have missed your fertile window. LH levels typically rise rapidly within a day, which can reduce the likelihood of detecting your surge. If you have a short or rapid LH surge, there’s more chance of missing it. Consider testing twice daily if you experience rapid surges. 

Other reasons for negative results include diluted urine or an anovulatory cycle. When you miss ovulation it’s called anovulation. Usually, hormonal imbalances can cause anovulation, but lifestyle choices and certain medications may also have an effect on your ovulation. If you are concerned, there are several steps your healthcare practitioner will take to diagnose any problem. 

If you need help knowing where to start, Mira’s fertility experts can be there to support and guide you as you learn about your options. 

Are Ovulation Tests Accurate?

OPKs and ovulation tests are approximately 99% accurate when taken and used correctly and for many can be the best way to track ovulation. They are highly accurate at detecting the rise in LH that spikes approximately 24-36 hours before ovulation that indicates your body is preparing for ovulation. They merely confirm the presence of luteinizing hormone (LH) rather than confirm ovulation has taken place. The accuracy of ovulation test strips does not equate to guaranteed ovulation.

Although some women ovulate like clockwork, not everyone has a predictable LH surge. If your LH levels rise and fall rapidly (short surge) with a very brief peak, you may miss your chance of detecting an LH surge. Consider testing twice daily within the predicted window to ensure you catch it.

Another source of accuracy issues with ovulation test strips is their sensitivity. The standard set by the FDA for a positive ovulation test strip is 25 mIU/mL, but brands can range from a threshold of 25 mIU/mL to 40 mIU/mL. Different brands use different thresholds based on the type of test they are and their target audience.

Factors That Can Skew Results

There are a number of factors that can skew the results of a standard LH ovulation test including varying LH peak patterns, PCOS, or even consistently high LH levels. The American Pregnancy Association also lists pregnancy, recent pregnancy, menopause, and certain prescription fertility medications as additional complication factors that could interfere with the results. 

LH surges look different across the population and standard test thresholds don’t work for everyone. Common LH surge patterns women experience include single surges, biphasic surges (two LH spikes), or plateaus. Not to mention that your lifestyle could influence test results. Sleep/work patterns can affect test timing and heavy fluids can also interfere with the results. 

The unpredictability of ovulation with PCOS can make tracking ovulation difficult and those with PCOS are likely to have elevated baseline LH levels. Traditional OPKs don’t always work but there are natural ways to support ovulation with PCOS: maintain a healthy weight, nourish your body, and limit stress. It sounds easy but implementing these supports can be challenging. Mira’s PCOS supplements are a great option to get the vitamins and minerals that can help balance hormones and promote ovulation. 

If you’re struggling to understand your OPK results for any reason (PCOS, irregular cycles, anovulation, etc.) consider consulting a professional who can help. Hormone health specialists can help you analyze your hormone results and provide expert guidance on all things PCOS. Unlike a doctor, they offer a practical and integrative approach on all things fertility - from a TTC plan with action steps to lifestyle changes - including choosing the right supplements to help you manage hormonal imbalance symptoms. 

How to Track Ovulation

There are a number of ways you can track and predict ovulation. Each method has pros and cons but you can combine methods for an even more thorough approach. 

Tracking LH levels in urine is one of the most accurate ways to anticipate ovulation. You can do this with ovulation test strips. If you track both cervical mucus and your LH levels, you’ll notice changes in your cervical mucus during your LH surge that is also a sign that your body will ovulate soon. To keep track of the look, feel, and consistency of your cervical mucus, we recommend using a cycle tracking app - such as the Mira App. It’s free to download and has a place to log cervical mucus characteristics alongside other key cycle data.

After ovulation happens, there is also a slight increase in basal body temperature (BBT). If tracked properly, BBT confirms ovulation but doesn’t predict it. When combined with other tracking methods, you can not only anticipate ovulation, but also more accurately pinpoint when ovulation occurred.

You can also use a more advanced method to track LH levels in urine with a hormone monitoring system - like the Mira Monitor and Wands. Mira tracks and predicts ovulation by tracking your hormones directly in a simple and non-invasive way. You can get precise daily hormone level readings, similar to those from a lab, and monitor your hormonal map over time through dynamic charts on your smartphone - clearly pinpointing your ovulation patterns.

Knowing your ovulation patterns can help you determine the best time to have sex whether you’re TTC or TTA. Although the general rule is to aim to have sex with your partner at least once every other day during your 6-day fertile window, you can target specific days when you are tracking ovulation and have sex once you get a positive test result if you’re trying to conceive. 

How to Test Ovulation Naturally at Home

There are a number of ways you can test ovulation naturally at home. They can be used in conjunction with other methods to help give you peace of mind and additional data on your cycle. 

Cervical mucus changes throughout your cycle and often resembles raw egg whites around the time of ovulation. By tracking the look, feel, volume, and consistency of your cervical mucus you can get to know your cycle and identify ovulation patterns. You can also use your cervical position to help track ovulation since it changes over the course of your cycle. You can keep track of your observations in a notebook or free app like the Mira App so you can notice patterns. 

Basal body temperature (BBT) charting can help you confirm ovulation since it rises slightly once ovulation has taken place. With the help of a special BBT thermometer, you can track ovulation by measuring and monitoring slight changes in BBT. This method isn’t as accurate as other methods and is best paired with hormone tracking for the most accurate results.

You can also track and detect ovulation through saliva testing. Using a small microscope provided in a saliva test kit you can examine saliva patterns as a sign of ovulation. Saliva testing doesn’t work for everyone, though and can be impacted by other activities so it’s best used as an adjunct rather than a standalone option.

Combining some of these methods can give you peace of mind as well as help you cross check your results. Getting a false positive or false negative can be a source of confusion or anxiety so multiple methods may help.

If you’re tracking ovulation naturally to prepare your body for conception, keep in mind that gentle cycle support can help. Vitamins like the Mira Prenatal Vitamins are an excellent source of micronutrient support that your fertility needs. There are even teas designed to help support your cycle, such as the Mira Fertility Tea. It can give you the gentle support you need while you prepare for what’s to come. 

Troubleshooting and Edge Cases

There are some cases when the best way to track ovulation may be difficult using OPKs. Irregular cycle lengths or hormonal conditions like PCOS can lead to less accurate results. If this is you, consider adjusting your testing period. You may need to start earlier, test longer, or test twice daily to capture your LH surge.

What happens if you never see an LH surge? There are many reasons for a negative result so before assuming the worst consider these other reasons for a negative result. First check that you are using the test correctly and following all the instructions. You may need a brand with a higher sensitivity or are testing at the wrong time. Try testing in the afternoon or even twice a day to get a positive result. Also, consider using a fertility monitor for more accurate results. A device like the Mira Hormone Monitor provides exact hormone levels and uses AI to learn your changing hormone patterns.

While a typical LH surge lasts 24-36 hours, some women experience multiple surges, which can wreak havoc on traditional testing and timing sex for conception. The key is to understand your body’s own unique pattern so you can time sex appropriately during ovulation. Your chances of conceiving are highest around ovulation so you should generally aim to have sex on the day of a positive test and the following day. If you suspect multiple surges, consider using a fertility monitor with numerical LH readings for more accurate peak detection (and intercourse timing).

If you’re getting positive results with ovulation test strips but still aren’t pregnant after several cycles, do not hesitate to seek personalized advice or further investigation. In addition to getting advice from your healthcare professional, you can also consult with Mira’s certified practitioners. They can help you understand if your reproductive health is affected or if it suggests a need for further investigation.

Sometimes there is an underlying issue behind your ovulation tracking struggles. There are many things that can get in the way of ovulation but it’s best to see a medical professional to get to the bottom of it. They will perform a thorough evaluation of your fertility situation to give you the best chance moving forward.

Conclusion

One of the best ways to track ovulation is testing for LH in urine. As we’ve seen, many people make use of ovulation test strips to track ovulation and capture their fertile window. Although over 99% accurate when used correctly, OPKs have many factors that affect their accuracy from testing errors to timing issues. Hopefully, in this article we’ve shed some light on how they work and how you can use them for conception. We’ve even covered some alternative methods for tracking ovulation naturally. Ovulation test strips can tell you a lot about your fertility, but consider integrating other methods for both accuracy and a bigger picture of your overall fertility.

Frequently Asked Questions

What might cause inaccurate ovulation test results?

Inaccurate results can be due to a number of factors including taking fertility medication, pregnancy, thyroid conditions, perimenopause, or PCOS. 

What does a positive ovulation test look like?

This depends on the type of test used. For paper based ovulation test strips a positive ovulation test strip will show two lines with the testing line darker than the control line. Digital ovulation tests show a clear symbol (“yes” or a smiley face) for positive results. Saliva testing will show fern-like patterns as it dries. 

Is it possible to use ovulation tests too early?

Technically yes. It can be tricky to know exactly when to test, especially if you have irregular cycles. Testing too early means you might miss ovulation or have to test again using up more tests. It can be helpful to track your cycle for a few months to get a better idea of when to test.

How often should I use an ovulation predictor urine stick test?

You have a better chance of catching your LH surge if you test twice a day. Your LH surge could be long or short and this gives you more opportunity to detect your peak. 

Why don't I get positive from my ovulation tests?

There are a number of reasons why you may not get a positive ovulation test strip including irregular cycles, testing too early or late, low LH levels (below test threshold), diluted urine, or medications affecting hormone levels.