First Response Ovulation + Pregnancy Tests
Why Test for LH Surge? Your two most fertile days begin with the LH surge. Therefore, you are most likely to become pregnant if you have intercourse within 24–36 hours after you detect your LH surge. The presence of two similar pink lines means you have detected your LH surge. The test line may be darker than the 4reference line. The presence of one line, or two lines with the test line lighter than the reference line, indicates that you have not yet reached your LH surge.