Does the hCG sensitivity of the test matter?
The sensitivity of a pregnancy test determines how soon after conception pregnancy can be detected by the diagnostic kit. Concentrations of hCG are reported in milliInternational Units (mIU) or amounts equal to 1/1000th of an IU per milliliter. Pregnancy tests with a sensitivity of 20 mIU/ml are more sensitive than tests with 50 to 100 mIU/ml. With 20 – 25 mIU/ml tests, high sensitivity equates to early detection of pregnancy. That means you can begin testing accurately as early as eight days after conception. Conception may take place several days after date of intercourse, so the date of intercourse should not be viewed as the necessary day of conception.