For couples trying to conceive, a proper understanding of a woman’s menstrual cycle and ovulation period is essential to reduce the time to pregnancy and associated stress.
In a perfect menstrual cycle, ovulation occurs on the 14th day, of a 28 day menstrual cycle. However, this only occurs in less than 20% of cycles among completely normal women making it difficult to time intercourse with ovulation. Fortunately, there are a few options available on the market to help women test whether or not they due to ovulate.
Ovulation sticks, sometimes also called ovulation predictor kits (OPKs) or simply ovulation test strips are urine-based tests that women can use at home to detect imminent ovulation. They are readily available and less intrusive than other methods (i.e. transvaginal sonography).
Ovulation test strips work by detecting a hormone called luteinizing hormone (LH) in the urine which rapidly increases (or surges) approximately 35 to 44 hours before ovulation.
Similar to other at-home hormone tests, ovulation test strips feature 2 lines. One line is the known as the control line which indicates if the test was used correctly and is working, while the second line is known as the test line.
For accurate results, ovulation tests should be performed on the second morning urine of the day, after a 2 to 3 hours hold.
Only One Line On Ovulation Test
Only one line (i.e. no second line) on the ovulation test happens if you test too early or too late in your cycle.
The majority of women (>75%), without any known conditions, ovulate anywhere between cycle day 12 to 17, meaning testing from cycle day 10 to 16 is most likely to identify your LH surge.
It is also normal for women to experience an anovulatory cycle once in a while, meaning no LH surge. However if this continues for a few months, please consult a medical professional.
Faint Line on Ovulation Test
A faint line on an ovulation test means your LH levels are currently below the LH threshold defined as a positive result.
Similarly, a faint line on an ovulation test after ovulation and before your period means your LH levels have dropped below the LH threshold set for a positive result.
Lastly, a faint line on an ovulation test does not imply you are pregnant.
Only two solid lines on an ovulation test, approximately 2 weeks after ovulation, would suggest you are pregnant. This is because at-home ovulation tests can not distinguish between LH and human chorionic gonadotropin (hCG) in your urine.
Do Ovulation Sticks Get Darker The Closer To Ovulation
Yes, the second line on an ovulation test (stick) becomes darker the closer a woman is to ovulation. This is because the levels of LH in your urine increases daily as you near the day of ovulation.
The day (or two) before ovulation, LH levels rise dramatically otherwise known as an LH surge. This means the second line on an ovulation test stick will become darker than the control line, and continue to be darker than the control line on the actual day of ovulation.
Two Lines On Ovulation Test
Two lines on an ovulation test indicates your LH levels is near or equal to the LH threshold set by the manufacturer on the control line.
However, this can mean a number of things depending on the colour of the 2 lines and which cycle day you did the test.
For example, two lines on an ovulation test, with one line (test line) lighter than the other (control line) before ovulation means your LH levels is nearing the LH threshold set for a positive result.
Alternatively, after ovulation, one line (test line) lighter than the other (control line) on an ovulation test, means your LH levels are declining back to baseline.
Finally, an ovulation test with two matching lines is a positive result indicating an LH surge.
How Long Will An Ovulation Test Stay Positive
An ovulation test can stay positive 1 to 2 days after the initial positive test. This is because the LH surge is sometimes longer or stronger than normal and therefore levels of LH in the urine have not dropped below the test threshold.
Three Lines On Ovulation Test
Three lines on an ovulation test is considered invalid due to poor manufacturing (i.e. defective).
Irrespective if you did the test during your fertile window (for LH), or outside your fertile window (for HCG).
You will have to do the test again to get an accurate result.
No Line On Ovulation Test
No control and test line on an ovulation test means the absorbent tip wasn’t saturated with enough urine, you have a rare condition, the ovulation test is defective or has expired.
Therefore, an ovulation test with no lines does not suggest you are pregnant.
Fortunately in the majority of cases, no lines on an ovulation test means the test is defective (or you have a rare condition). This is easy to check by doing the test again.
You can also ask your partner do the test (as males have the same hormone) to confirm you have a faulty batch of OPKs.
Two Lines On Ovulation Test, Could I Be Pregnant
Two lines on an ovulation test could indicate you are pregnant if the test was performed approximately 2 weeks after ovulation.
This is because LH is molecularly similar to the pregnancy hormone human chorionic gonadotropin (hCG) and at-home ovulation tests can not distinguish between the two hormones.
In fact, the majority of ovulation tests use a LH test threshold of 25 mIU/ml. This means in theory ovulation tests could detect hCG levels above this threshold 12 days after ovulation following successful conception.
However, ovulation tests are not as reliable as pregnancy tests in detecting pregnancies and it is recommended to use the latter to confirm you are pregnant.
A Tip From Fertility Science
Although ovulation tests are a simple and effective way to help predict ovulation, they are by no means perfect.
In one study, positive ovulation tests failed to correctly predict ovulation within 24 hours, in approximately one-third to one-half of cycles, among completely normal women.
However, the same study also found that the simultaneous use of cervical mucus and ovulation tests improved the prediction of ovulation in the same women.
To summarize, on their own OPKs are not a miracle treatment and do not decrease the time-to-pregnancy significantly. This is because there are many others factors which contribute to successful conception other than timed intercourse.
Nonetheless, ovulation predictor kits (OPKs) allow women to understand their cycles better and seek medical assistance earlier (if required), which does indirectly decrease the time-to-pregnancy.
In the future, next generation OPKs will hopefully be able to differentiate between the 3 types of LH (intact LH, LHβ and LHβcf) to help women pinpoint the real LH surge from urine samples.
References
Demir A, et al. (2022). Identification of the LH surge by measuring intact and total immunoreactivity in urine for prediction of ovulation time. https://doi.org/10.1007/s42000-022-00368-9
Yeh P T, et al. (2019). Should home-based ovulation predictor kits be offered as an additional approach for fertility management for women and couples desiring pregnancy? A systematic review and meta-analysis. http://doi.org/10.1136/bmjgh-2019-001403
Su H W, et al. (2017). Detection of ovulation, a review of currently available methods. https://doi.org/10.1002/btm2.10058
Direito A, et al. (2012). Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women. https://doi.org/10.1016/j.fertnstert.2012.08.047
Cole L A, (2010). Biological functions of hCG and hCG-related molecules. https://doi.org/10.1186/1477-7827-8-102
Park S J, et al. (2007). Characteristics of the urinary luteinizing hormone surge in young ovulatory women. https://doi.org/10.1016/j.fertnstert.2007.01.045
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I started taking the opk 4 days ago. Day 1 the test line was very faint. Day 2 the test line was slightly darker, but still faint. Day 3 the test line was much darker but not quite as dark as the control line. Day 4 the test line is very faint again. I read that the test line should gradually darken as ovulation gets closer so why did my line get lighter before ovulation/a positive test result has occurred? All tests were taken with first morning urine after at least 4 hours of not urinating. Is it possible I may still get a positive test this month? Or does the decline in test line darkness mean my LH is declining and will not go back up? Thank you.
Hi Amanda,
Ideally speaking LH levels will gradually rise as you near ovulation and then surge (or spike) approximately 1-2 days before ovulation.
However a study in 2007 clearly demonstrated that a woman’s changing LH levels is rarely textbook perfect and instead describes 3 types of LH surges (Spike, Biphasic and Plateau). https://www.fertstert.org/cms/attachment/c02cf906-51c3-4b6c-ad4e-1755179b5080/gr3.jpg
So to answer your question, it is possible that your LH level may rise again (and possibly test positive) but you will have to continue testing further into your cycle.
Hope this helps!
Kind regards,
Fertility SCIENCE
Hi, in my experience with OPKs and pregnancy my test never was as dark as the control line but I still got pregnant. I bet your surge was at a different time in the day than you tested so you didn’t see that really dark line. Hope that helps!
The days leading up to my fertile window on my app, my tests we slowly getting darker day by day.
The tests eventually became very close to the control line and the day I ‘ovulated’ on my app it became significantly lighter.
I was testing on my 2nd wee of the day.
I never saw my test get darker than the control line.
Does this mean I did not ovulate?
Hi Hannah,
As you know OPK’s do not confirm ovulation. However it sounds like you had a less than ideal surge in LH. Given it was a gradual LH rise and not really a ‘surge’, it is highly unlikely you ovulated that cycle.
Hope this helps a little!
Kind regards,
Fertility SCIENCE
Hi, I am Edith
I get a really low LH test result in the morning but gets much deeper test line in the evening although not as dark as the control line. And my period tracker says, I should be ovulating the next day. It’s confusing
Hi Edith,
It’s difficult to say without more information however your hydration levels will significantly influence the result of urine based tests such as OPK’s.
For this reason, experts usually recommend women to test once a day in the morning, with your first urine of the day. This is normally when your LH levels in the urine are most concentrated and consistent. This is particularly important with OPK’s as you are testing low levels of LH prior to the actual LH surge.
On that note, please be mindful that not everyone’s LH surge is textbook perfect so you may still see some variability every 24 hours assuming identical hydration levels. For this reason it may be helpful to capture (or note) the colour of your urine every test to better understand any fluctuations.
Overall, OPK’s will always be more accurate than a period tracker by design. However they are by no means perfect and most Doctors will still recommend couples to have sex every day (or other day) during their fertile window.
Hope this helps!
Kind regards,
Fertility SCIENCE
Much clearer now. Thank you. Appreciated
Pls I did the Ovulation test, the Control line was very deep but the first line was faint but as time went on the first line darkened and thin but not as broad as the Control . What does that mean ,am confuse
Hi Anita,
It honestly sounds like the ovulation tests you have are poorly manufactured (although they seem to be working correctly).
Our recommendation would be to buy another brand regardless just for peace of mind.
Kind regards,
Fertility SCIENCE
i took an ovulation test and it came back as positive with 2 solid lines i’m currently 7 days late for my period but no positive pregnancy test yet which i think is odd. should i assume that i’m not pregnant.
Hi Cassie,
Just to clarify, is the ovulation test showing 2 solid lines currently? Or do you mean you had a positive ovulation test mid-cycle and are now 7 days late for your period?
Kind regards,
Fertility SCIENCE
I’m 8 days late for my period and took an ovulation test because my friend said to and it’s showing 2 solid lines
Hi Cassie,
Ovulation tests are not as accurate (or specific) as pregnancy tests for the pregnancy hormone HCG. Without going into the science of these tests, this explains how your ovulation test can be positive but your pregnancy test negative at the same time.
For reference, the majority of reputable at-home pregnancy tests have a 99% accuracy rate on the day of expected period (according to the natural rise in HCG levels after successful implantation). This accuracy rate increases further, with each passing day as HCG levels in the body increase by approximately 50% a day.
Based on these numbers, it is highly unlikely you are pregnant, if as you say you had a negative pregnancy test approximately 3 weeks after ovulation (regardless of the positive ovulation test).
Kind regards,
Fertility SCIENCE
Hi took an ovulation test today the control line was dark but the test line was lighter and thinner. My cycle app says today was ovulation day but I think I ovulated shortly after my cycle. How will I know it’s confusing
Hi Angelify,
OPK’s are definitely more accurate than apps which use body temperature to predict ovulation.
A lighter test line means your level of LH has not quite reached the threshold set by the manufacturer for a positive reading.
The only way to know if this result is because you have not ovulated yet or if your LH surge is ‘milder’ or different to the ideal LH surge, is to continue testing over the next 4 to 5 days.
If the test line continues darkening, it’s safe to assume you have not ovulated yet, and will shortly after the test line and control line match in colour.
However, if the test line does not continue darkening and instead fades away, you may have a less than ideal LH surge type. In this scenario, reading your cervical mucus simultaneously would help you to better confirm upcoming ovulation in future cycles.
Hope this helps!
Kind regards,
Fertility SCIENCE
I took an ovulation test today and both lines are dark on an app that I use it read high and it shows 0.96 , I’ve never done this before so I’m not sure how many does until I ovulate or I am ovulating, can someone explain please
Hi Lianna,
Apps which read the OPK test for you usually compare the colour of the test result line to the control line digitally. The number given (0.96) is how close the test line is to the control line (or Test / Control ratio).
A perfect match is 1.00 (also known as a positive reading).
(A reading higher than 1.00 represents LH levels higher than the OPK test threshold.)
Given how close your reading is to perfect, you may only be half a day away from a positive reading.
Once you obtain a positive reading, you are 50-60% likely to ovulate within the next 24 hours.
To improve this accuracy, you could read your cervical mucus or test for progesterone (metabolite) levels.
Hope this helps!
Kind regards,
Fertility SCIENCE
Please I tested today and it shows two lines the first line is faint and the second line is darker what does it means
Hi Helen,
One line should be the control line, which is dark. This means the test is working correctly.
The other line is the test line. This usually appears faint, and becomes darker, as your level of LH increases. This test line is considered ‘positive’ when it matches the control line colour.
If you have a third line appear, the test is invalid and you will need to retest.
Hope this helps!
Kind regards,
Fertility SCIENCE
I had to faint lines showing on the ovulation test but the test shows it has to be two dark lines so I’m confused am I ovulating or am i reading too much into it
Hi Teebee,
No you are definitely not reading too much into it.
It is very likely you are having an LH surge but from a scientific point of view a very faint control line would be considered invalid due to poor manufacturing (i.e. defective).
Please try another test from a different batch if you can to confirm beyond any reasonable doubt.
Hope this helps!
Kind regards,
Fertility SCIENCE
Hi,
I did ovulation test today. It came positive. But the line is 2 . Is that mean I am pregent
Hi Renuka,
An ovulation test (OPK) which shows 3 lines (i.e. 2 test lines and 1 control line) is considered invalid due to poor manufacturing (i.e. defective). Regardless if you did the test during your fertile window (for LH), or outside your fertile window (for HCG).
Unfortunately you will have to do the test again to confirm you are positive (i.e. 1 test line and 1 control line) and due to ovulate.
Hope this helps!
Kind regards,
Fertility SCIENCE
I took an ovulation test its showing 2 lines that are the same. Last week I had spotting and last Saturday night I had a positive pregnancy test and it was negative on sunday morning what does all that means
Hi Crystal,
Ovulation tests detect both LH and hCG (the pregnancy hormone) since they’re molecularly similar. Therefore a positive ovulation test 2 weeks after ovulation could indicate you are pregnant but please confirm this with a proper pregnancy test kit.
Regarding the inital positive and then negative pregnancy test, hormone levels actually fluctuate hour to hour somewhat whilst trending up, down or sideways. This means taking pregnancy tests within 12 hours of each other, during the first day or 2 of implantation, could give you the positive and then negative result you saw.
Hope this helps a little!
Kind regards,
Fertility SCIENCE