There is another cause of false positive hcg test results that is unique to blood samples.
False positive pregnancy blood test results.
A false positive test result a positive human chorionic gonadotropin hcg test result when you are not pregnant can occur for a variety of reasons.
First a quick summary.
It s also possible to get a false positive result if your body produces certain types.
It may cause a false positive reading on an at home pregnancy test particularly if the test is taken too early.
Other medications can also cause false positive pregnancy tests.
Wrong results with blood pregnancy tests a blood test might not detect human chorionic gonadotropin hcg even when a woman is pregnant if the test is done too early.
A phantom hcg causes a positive blood pregnancy test without being pregnant.
Most over the counter pregnancy tests measure the levels of hcg in a woman s urine.
Human blood normally contains many different types of antibodies.
But they can cause the body to start producing hcg which could get picked up on a pregnancy test and cause a false positive reading.
It takes at least seven days after fertilization for the test to become positive.
After an abortion or miscarriage a home pregnancy test may produce a false positive result since the levels of hcg in the body may still be relatively high.
Molecules made by our immune system that identify and neutralize invaders such as bacteria and viruses.
As with urine home pregnancy tests it is possible to end up with false results both negative and positive from a blood pregnancy test.
Taking a home urine pregnancy test.
Intact hcg reduced the number of false positive pregnancy test results from 13 to 1 a 92 reduction 95 ci 64 99 corresponding to a reduction in the false positive rate from 38 95 ci 22 56 to 3 95 ci 1 15.
A false negative test is negative but you re pregnant can occur if the blood pregnancy test was performed too early.
