The test is done by analyzing the levels of luteinizing hormone in the urine with a test strip. You can buy the LH test strips in our shop or in your local pharmacy. The tests are commonly known as "ovulation tests" or OPKs (ovulation prediction kits).
LH is always present in the body, why you can often see a light second band on the strip. But it's only when both bands are equally strong that the test is considered positive (Natural Cycles branded LH tests - please check the manufacturer's information if using another brand of LH tests). LH tests are optional, and not a requirement for the algorithm.
An increased LH is usually found within 24-48h before ovulation. Natural Cycles app lets you know by indicating "LH" in the prognosis on the days you should take an LH test, and you see these in the Month- and Today view. These indications are optimized so that you have to take as few tests as possible without missing your peak. You can of course always take as many tests as you want anyway. Just enter the test results in the app as usual.
1) Measure between 10am-8pm as the LH-levels tend to rise during the day. Use concentrated urine (i.e. make sure you haven't visited the bathroom or taken in a lot of fluids the 2 hours prior to testing). Collect a urine sample in a clean and dry container.
2) Open the package and take out the strip. Do not open the package until you are ready to test.
3) Dip the strip vertically into the urine sample. Keep it in the sample for at least 10 seconds. Do not allow the urine to go above the MAX level line.
4) Place flat on a clean, dry surface.
5) Wait for colored bands to appear. Depending on the concentration of LH in the urine, positive results may be observed as short as within 40 seconds. However, to confirm a negative result, the complete reaction time of 10 minutes is required. Do not read the results after 30 minutes.
You can repeat this procedure as many times a day as you wish to. Especially if you see a second colored band, but it's not strong enough to be considered positive it can be a good idea to test a few hours later.