For women trying to become pregnant, a false positive pregnancy test can be a devastating discovery. While the sensitivity and specificity of pregnancy tests has improved dramatically over the years, there are still some conditions that will lead to results that are inaccurate. Understanding what causes these false positive results can better prepare women for the uncommon occurrence of getting a result that isn’t necessarily accurate.
False Positive Pregnancy Tests in Lupus Patients
In regards to pregnancy tests, those with lupus have been found to have increased false positives. The Journal of Rheumatology has recently reported that these erroneous results may be linked to the increased amounts of protein that are passed in the urine of patients who have lupus.
ANA Test Positive
Patients who have previously been tested for lupus and had a positive ANA test yet didn’t meet all of the lupus diagnostic criteria should consult their physicians if they are found to have a pregnancy test that is erroneously positive. These patients may not have previously met the criteria for diagnosis, but now with having a false positive pregnancy test, physicians may need to reevaluate the situation.
IgA Deficiency
Researchers have found that patients with deficiencies in immunoglobulin A have increased instances of pregnancy tests that report incorrectly as positive. In patients with this immune disorder, higher levels of beta human chorionic gonadotropin (hCG), also known as the pregnancy hormone, have been noted in blood tests. This was the first study of its kind to find this phenomenon occur in these patients. Previously, patients were thought to have molar pregnancies when positive hCGs were found in IgA-deficient patients. It is now understood that these results must be interpreted with caution as there may be cross-reactivity with the testing mechanism and the patient’s disease state.
Other Health Issues that Cause Inaccurate Results
There are other common health conditions that can cause a pregnancy test to be falsely positive. These include the following:
- hydatidiform mole (molar pregnancy)
- miscarriage
- ovarian tumors
- other tumors
If patients receive a positive pregnancy test and have every reason to believe that they are not pregnant, they need to discuss the phenomenon with their physicians. It is important to note that the chances that a pregnancy test is falsely positive is very low, so any patient receiving a positive test should consult a physician for follow up care as soon as possible.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Choosing the best method for treating your illness is a decision that you and your doctor can discuss together. Any reader who is concerned about this issue should contact a doctor for advice.
Sources:
PubMed.gov: False positive pregnancy tests in systemic lupus erythematosus (Accessed January 29, 2011)
Lupus Foundation of America: The Antinuclear Antibody Test (Accessed January 29, 2011)
Lab Tests Online: ANA (Accessed January 29, 2011)
PubMed.gov: Frequent false positive beta human chorionic gonadotropin tests in immunoglobulin A deficiency (Accessed January 29, 2011)
Join the Conversation