The Clinical Guard LH urine ovulation test is a fast-acting ovulation test. It works by detecting the presence of luteinizing hormone "LH" in urine. LH increases dramatically just before ovulation which is a woman's most fertile time of the month to conceive. The increase in LH also known as LH surge is the hormonal change that precipitates ovulation. The Clinical Guard HCG urine test is also a fast-acting pregnancy test. It works by detecting the presence of human chorionic gonadotropin "HCG" in urine. If your result is positive, please contact your physician. He or she will be able to confirm your pregnancy. If your results are negative and you have reasons to believe that you are pregnant e.g. delayed menstruation, you should repeat the test after a few days. The Clinical Guard test takes just a few seconds to collect your urine, and five minutes to obtain results. Note: The color intensity of the test bands on the test vary depending on the concentration of LH hormone detected.