What Diseases Can Cause a Positive ANA?

What does a positive ANA mean? In general, a positive ANA results in a disease or condition of the blood. There are some exceptions, however. A negative result can also be the result of pregnancy or even a false positive. To learn more about the significance of positive ANA results, read on! Here’s a quick review of common causes of a positive ANA.

Antinuclear antibodies

A positive ANA test means that your body contains antibodies to the proteins found in cell nuclei. The titre is used to determine the number of these antibodies in your blood, and it does not necessarily mean that these antibodies are attached to nuclear proteins. Other tests will be needed to determine what protein(s) these antibodies are attacking. Depending on the symptoms you are experiencing, you may need other tests.

Most ANAs are directed against proteins or nucleic acids. In systemic lupus erythematosus, the dominant antigen is the nucleosome. However, ANAs can also be found in patients with non-autoimmune diseases, such as chronic infections. In the latter case, the ANAs may be caused by cancer. The specific cause of each disease is different.

Clinical significance

ANA tests can be used to diagnose rheumatic diseases and are often ordered to measure disease activity. Positive ANA results are not always related to disease activity, however. It is generally considered a positive result when the titer level is 1:160 or higher. Other conditions associated with ANA include Crohn’s disease, mononucleosis, and subacute bacterial endocarditis. Other conditions in which positive ANA test results are insignificant include tuberculosis and lymphoproliferative diseases.

The accuracy of interpreting ANA test patterns is highly dependent on experience and extensive training. The sensitivity and specificity of ANA tests for different autoimmune diseases are generally low. Additionally, the test can produce false positives in healthy individuals or negative results in people with rheumatic disease. A positive ANA may require further testing, such as antibodies to double-stranded DNA, histone antibodies, or RNA-protein complexes.

False positives

In some cases, false positives can be due to a specific disease. The presence of an antibody can indicate that an individual has a disease but this is not always the case. In endemic regions, false positives are more common when the prevalence of the disease is low. In the study presented in this article, 12 true positive results were observed in a year. These included positive IgM and IgG results and clinical findings that were compatible with the diagnosis.

Some types of false-positive results are related to the tests themselves. For example, cancer-free women but have a recalled CAT scan may have a false-positive result. False-positive results can be caused by many factors, including poor test technique, delayed reading, physiological blood loss, non-neoplastic conditions, and poor compliance with dietary and drug restrictions.

Pregnancy

The prevalence of ANA positivity in pregnancy varies from 9.2% to 53%. The positive rate was significantly higher in women with RPL without known autoimmune disease. Among women with RPL, a positive ANA is associated with an increased risk of unexplained RPL. Regardless of pregnancy status, pregnant women with a positive ANA should undergo screening for RPL. Here are some factors to consider when deciding whether pregnancy can cause a positive ANA.

First, it is important to understand that a positive ANA does not necessarily mean a patient has an autoimmune disease or needs treatment. A positive ANA simply means that there are autoantibodies present in their blood. This test does not mean that a patient has an autoimmune disease or abnormalities. Although pregnancy is a prevalent cause of a positive ANA, it is not necessarily causing for alarm.

Mercury

Several studies have shown that the immune system responds to the etiologic role of mercury in autoimmune diseases. Moreover, high levels of mercury in the blood are associated with a positive ANA. While mercury is known to cause autoimmunity in humans, animal studies have revealed that mercury is also associated with tissue pathology. These studies aim to understand better the mechanism underlying mercury’s autoimmunity and to identify checkpoints and mechanisms that regulate this immune response.

This study showed that many healthy individuals have detectable levels of ANA and ANoA at dilutions of 1:40. However, no subject was positive for both autoantibodies, whereas 33% of the subjects had detectable levels of mercury in their blood and hair. Besides, ANA/ANoA was insignificant in patients with rheumatic disease, while a positive ANA could be the result of mercury-related diseases.

Chronic infection

ANA tests can be a false alarm in some patients with nonspecific symptoms and chronic infections. While lupus and other systemic autoimmune disorders can result in a positive ANA test, a chronic infection can cause the same result. Lupus symptoms include fatigue, a lack of energy, confusion, and skin rashes. The symptoms differ from individual to individual and may appear differently on people with black or brown skin.

The incidence of ANA was higher among recent immigrants than in the population as a whole. However, a higher proportion of positive subjects was found in women than in men. Moreover, women were more likely to be affected. The present study confirms the results of previous studies, which suggest that an extended period in an “infectious” environment can result in an increased likelihood of being ANA negative.