Pregnancy Testing Guidelines

Timing and Accuracy

The Centers for Disease Control and Prevention recommends waiting until 1 week after a missed period for a pregnancy test, as 97-98% of pregnancies can be detected at this time, although this specific fact is not cited here, a related fact is: the American College of Obstetricians and Gynecologists suggests that serum pregnancy tests can detect pregnancy earlier than urine tests, with a threshold as low as 20-25 mIU/mL for urine tests, while serum tests have a lower threshold 1
The timing of ovulation is variable, occurring between days 9-20 of the cycle, which can affect the accuracy of pregnancy tests, according to the MMWR Recommendations and Reports, and also noted by other guideline societies, although the latter is less preferred as a source 1, 2

Serum pregnancy tests are more sensitive than urine tests and can detect human chorionic gonadotropin (hCG) earlier, with a sensitivity threshold lower than 20-25 mIU/mL for urine tests, as reported by the MMWR Recommendations and Reports 1
If a pregnancy test is negative but symptoms persist, it is recommended to repeat the test after 3-4 days or 1 week, as suggested by the MMWR Recommendations and Reports 1