Most home pregnancy tests claim to provide 99 percent accurate results on the first day after a missed period. However, experts recommend waiting up to seven days to get the most accurate results, according to the Office on Women's Health, U.S. Department of Health and Human Services' website.
According to the Office on Women's Health, a woman should contact a physician immediately if a home pregnancy test yields a positive result. A physician can perform a more sensitive test and conduct a pelvic exam to confirm pregnancy. A visit to a physician early in the pregnancy increases the chances for a healthy baby and mother.
If a home pregnancy test is negative but a woman's period does not begin, the Office on Women's Health advises taking the test again within a week. Due to differences in ovulation and implantation from woman to woman, accuracy in tests may vary.