hCG from other sources: Human chorionic gonadotropin (hCG) is the hormone that HPTs test for. If you are taking hCG for infertility or for weight loss, this can cause a false-positive result. hCG can also come from different sources. For example, tumors associated with gestational trophoblastic disease can produce hCG and can cause a false-positive result.
Defective or expired HPT: Check the expiration date on the package to make sure it hasn't expired. Getting a defective HPT is very rare, but it can happen. False-positive results are most often linked to tests that use the + or – rather than two lines or words. If the result isn't clear or you can't decipher it, test again, perhaps with a different brand.
Chemical pregnancy: Your positive result may actually be true. But if you test the following day and you get a negative, you may have had an early miscarriage or chemical pregnancy. This is most commonly caused by a genetic defect that "corrected" itself by not allowing the pregnancy to continue. These happen about 15 percent of the time. Modern HPTs are able to detect a pregnancy before a missed period, so if you wouldn't have tested, you probably wouldn't have even known.
Contamination: Be careful not to touch the stick or the cup with soapy hands, and use a clean plastic cup each time. Soap can cause a false-positive result. Blood or protein in the urine can also cause a false-positive result. This can be due to a number of illnesses, such as diabetes, bladder infection, kidney infection, etc.
What to Do About a False-Positive Pregnancy Test
There are a couple options here. First, remember that false positives are rare, so you could try testing again with a different brand to see if you get the same result. HPTs are said to be 97 percent to 99 percent effective when the directions are followed exactly.
If you keep getting mixed or confusing results and want to know for sure, the best option is to schedule a doctor appointment to get your blood drawn. This method is the most accurate test to confirm a pregnancy. Pregnancy can be a life-changing event, which makes being sure even more important.
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