False pregnancy test results

[mcraig]

I know it's possible for pregnancy tests to give a false negative, but is it all possible that a test would give a false negative and if so how common is it?

[daffy654]

Do you mean is it possible to get a false POSITIVE? If so it is possible but extremely uncommon. Try using one of the more expensive tests such as Clearblue if you are concerned about any result. They tell you in words the result rather than a line.

[mountainboo]

Hi,
False positive pregnancy tests are rare - though there are instances and conditions where they can occur.
I found this info for you:

Missed Reaction Time
For accuracy in home pregnancy tests it is essential that you read the test results in the stipulated reaction time. If you let the test sit for too long (after the instructions on the box tell you), the test is invalid. This may cause it to show false positive results.

Chemical Interference
Drugs that have the pregnancy hormone Human Chorionic Gonadotropin (hCG) in them can cause incorrect results in home pregnancy tests. The Human Chorionic Gonadotropin (hCG) in them may be responsible for the false positive pregnancy test. If you have had an HCG shot due to infertilty treatments, you need to be sure the shot is out of your system before you attempt to use early pregnancy tests.

Evaporation Lines
While technically not a true pregnancy, some pregnancy tests leave a faint evaporation line as the urine crosses the test. This faint very light grey evaporation line in the test area is often interpretted as a positive result.

I think in reality it is quite rare x