There are two things to be concerned about with home pregnancy tests. 1. false positives and 2. false negatives.
False positives would be if the pregnancy test tells you that you are pregnant, but you really aren't. With most home pregnancy tests, false positives are extremely rare, in fact, almost non-existent. Chances are if the test reads positive - you are pregnant.
Exceptions happen if you have been taking certain hormones, or have recently been pregnant and there are still hormones in your system. Either way, a positive test is worth a call to the doctor.
False negatives are a little more common. They happen when there isn't enough of the pregnancy hormone in your system yet to cause the test to react positively. Each type of pregnancy test has a different threshold - some are more sensitive than others.
If you think you have a false negative, check the packaging for the pregnancy test you took and try a different one that's more sensitive. You can always call your doctor who can provide a blood test that will be extremely accurate.
It is always a good idea, if you think you are pregnant, to call your doctor.
