The earliest a pregnancy test can be taken after conception is generally about 8 to 10 days, as this is when the hormone hCG (human chorionic gonadotropin) starts to be detectable in urine. However, most tests are most accurate from the day your period is due, which is usually about 12-15 days after ovulation or conception. More sensitive early-detection tests can sometimes detect pregnancy a few days earlier, around 6-10 days after ovulation or implantation. Waiting until the first day of a missed period or after improves the reliability of the test results and reduces false negatives. In summary:

• Earliest detection: Around 8-10 days after conception with sensitive tests.
• Typical accurate testing: From the day your period is due (about 12-15 days after ovulation).
• For best accuracy, test at the time of missed period or later.

This timing is related to when the fertilized egg implants in the uterus (6-12 days after ovulation), triggering hCG production detectable by tests 3-4 days after implantation.