Can antibodies affect hCG levels?
Can antibodies affect hCG levels?
High levels of hCG can overwhelm the antibodies that pregnancy tests use. When too much hCG is present in a sample, the antibodies may fail to bind, and the test will appear negative.
Why does IgA cause false positive pregnancy test?
A patient with IgA deficiency had a series of positive serum pregnancy tests which led to medical and surgical procedures for suspected molar pregnancy. These tests were found to be falsely positive due to heterophile antibody.
What is the role of Heterophile antibodies?
Heterophile antibodies are antibodies induced by external antigens (heterophile antigens). Some cross-react with self-antigens. For example, in rheumatic fever, antibodies against group A streptococcal cell walls can also react with (and thus damage) human heart tissues. These are considered heterophile antibodies.
Why do ovarian cysts cause false positive pregnancy test?
Ovarian Cysts With time, it disintegrates and the cycle is repeated. If the corpus luteum fills with blood or fluid, it becomes a cyst and remains on the ovary. The corpus luteum produces HCG, and can therefore interfere with the accuracy of a pregnancy test.
Can you be pregnant without HCG?
A pregnancy where there is little or no detectable HCG (human chorionic gonadotropin) in the mother’s system and even the fetus may go undetected by doctors, until delivery. HCG is the hormone that makes a home pregnancy test turn positive. A baby that produces very little amount of HCG might fail the pregnancy test.
What causes positive heterophile antibody test?
A positive test means heterophile antibodies are present. These are most often a sign of mononucleosis.
Can LH cause positive pregnancy test?
False positive results occur in 5/1000 tests and can result from (CG) being present in hydatidiform mole and choriocarcinoma; follicle-stimulating hormone (FSH) or luteinizing hormone (LH) can also trigger positive results.
Can ovarian cysts cause hCG to rise?
Conclusion: Mature ovarian cystic teratomas have rarely been reported to secrete HCG. They can be an infrequent source of HCG production and may lead to emergency surgery to treat a suspected extra-uterine pregnancy.
Can a heterophile antibody prevent a false positive?
These cases illustrate that serum heterophile antibodies can interfere with the hCG enzyme immunoassay and result in false positive values. The addition of heterophile blocking agent to the serum can exclude false positives, thereby preventing unnecessary evaluation and treatment.
Can a heterophile antibody block beta hCG?
Serum beta-hCG levels for both patients were negative after pretreatment of their serum with a heterophile antibody blocking agent. Conclusion: These cases illustrate that serum heterophile antibodies can interfere with the hCG enzyme immunoassay and result in false positive values.
How are heterophile antibodies used in immunoassays?
Heterophile Abs, because of their multi-specificity, are capable of binding to different components of an immunoassay. This can include the antigen or the analyte of interest, such as the endogenous analytes from the patients, or even the labelled analyte from the assay reagent.
Is the hCG assay susceptible to heterophile interference?
Among immunometric assays, human chorionic gonadotropin (hCG) assays have been found uniquely susceptible to heterophile antibody interference, resulting in occasional false-positive results. The current assay has proven robust in this respect, but rare interferences still occur.
