the hCG sensitivity of pregnancy tests differ?
choosing a pregnancy test, they vary wildly in the levels
of hCG the tests detect. And the lower the level listed on
the kit, the more sensitive to the presence of hCG it is,
not the other way around like many believe.
For pregnancy testing,
the concentrations of hCG are reported in milli International
Units (mIU) or amounts equal to 1/1000th of an IU per milliliter.
In simpler terms that you will find listed on the test box,
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, this means the test can determine pregnancy much earlier
than the ones in the 50 to 100 mIU/ml range. If you are past
your period due date, choose a test in the 50 to 100 mIU/ml
range, as they are usually much less expensive.
However, if you
are trying to conceive and want to know sooner, you might
find it worth the expense to buy a pregnancy kit in the 20-25
mIU/ml range. You can begin testing for pregnancy as early
as eight days after you believe conception might have occured.
Also keep in mind that conception can take place up to three
days after intercourse
That means you
can begin testing accurately as early as eight days after
conception. Conception may take place several days after date
of intercourse, keep this in mind when you plan the date for
pregnancy testing for each cycle.