The urine pregnancy test checks for the presence of the pregnancy hormone hCG human chorionic gonadotropin. hCG made by the placenta which exists only in pregnancy. A positive test that was done correctly has a 99% reliability that you are pregnant. A positive pregnancy test usually means that you are pregnant. There are only a very few circumstances in which a positive pregnancy test means that you are not pregnant (False Positive Test).
Reasons for false positive pregnancy tests include the following:
- Fertility treatment: If you receive shots of hCG or gonadotropins (for example, Pregynl, Profasi, Pergonal, APL) for ovulation it's posible to have a positive urine or blood pregnancy test for two to three weeks after the shot and not be pregnant. A rising blood hCG level usually indicates a pregnancy.
- Evaporation line. If you read the test incorrectly and after the suggested time has passed.
- Chemical pregnancy
- Certain rare medical conditions such as trophoblastic disease, or islet-cell tumors
- Some drugs like Methadone, chlordiazepoxide, or promethazine can give a false positive pregnancy test
- The most important false positive blood test is a "Phantom hCG" false positive pregnancy test
Updated: 10/6/2005 5:31:00 AM