What is an ANA Test?

Karyn Maier
Karyn Maier

An ANA test, also known as the antinuclear antibody test, is designed to detect antinuclear antibodies in a sample of blood. The acronym ANA refers to antinuclear antibodies that are automatic in the sense that they automatically bind to certain surfaces within the nucleus of cells. While a healthy person should possess a certain amount of antibodies to guard against invading bacteria, antinuclear antibodies work against this self-defense mechanism. In fact, a high level of antinuclear antibodies present may indicate that the immune system is capable of mistakenly launching an attack on healthy tissue. This condition is known as autoimmunity.

An ANA blood test helps detect antinuclear antibodies.
An ANA blood test helps detect antinuclear antibodies.

The ANA test was developed by Dr. George Friou in 1957 to help diagnose autoimmune disorders. Most commonly, an ANA test is performed when lupus is suspected. However, the clinician may order an ANA test to rule out various other autoimmune disorders when certain symptoms are present, such as frequent joint pain, skin rashes, chronic fatigue, or a persistent low-grade fever. Additional blood tests may be performed in addition to the ANA test, to include erythrocyte sedimentation rate (ESR) and/or C-reactive protein (CRP) tests. Often, the results of each blood test can be determined from a single serum sample.

An ANA test might be administered when someone has a persistent low-grade fever.
An ANA test might be administered when someone has a persistent low-grade fever.

ANA tests allow the clinician to examine how certain antibodies react to the nucleus of cells In vitro. When a reaction is observed, they are then said to be antinuclear antibodies. Sometimes, it is necessary to use fluorescence tools to determine if there is an antinuclear reaction. For this reason, the ANA test is sometimes referred to as the fluorescent antinuclear antibody test, or FANA.

Antinuclear antibodies, or ANAs, can also be present in patients without autoimmune disorders. For instance, ANAs may be detected in those afflicated with kidney, liver, breast, or other types of cancer. ANAs may also be found in persons with chronic infectious diseases. In addition, a positive ANA test result may occur in subjects with Crohn's disease, Grave's disease, ulcerative colitis, Addison disease, rheumatoid arthritis, and many other disorders. In addition, about five percent of the population exhibits low levels of ANAs without any disease being present.

A positive ANA test result may also be drug-induced. For instance, procainamide, dilantin, and hydralazine are medications known to promote the production of ANAs. In this case, the elevated levels of ANA may not be related to any disease. However, if a disease is diagnosed, it is said to be a drug-induced disease.

Aside from determining the number of ANAs present during an ANA test, the clinician also observes ANA patterns. Specifically, this observation is dependent on the type of stain used on the nucleus of the cell, which results in homogeneous or diffuse, peripheral or rim, speckled, or a nucleolar pattern. No one pattern is specific to any particular disease. However, certain diseases are more commonly linked to certain patterns. For instance, the nucleolar pattern is most commonly found in people with scleroderma.

Blood tests to check CRP and ESR are often conducted in conjunction with an ANA test.
Blood tests to check CRP and ESR are often conducted in conjunction with an ANA test.
Karyn Maier
Karyn Maier

Contributing articles to wiseGEEK is just one of Karyn’s many professional endeavors. She is also a magazine writer and columnist, mainly for health-related publications, as well as the author of four books. Karyn lives in New York’s Catskill Mountain region and specializes in topics about green living and botanical medicine.

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Discussion Comments

anon148271

I'm suffering from skin rashes, specially on the exposed area, for ex: neck, face specially including ears, hands or some areas of my arms. when i go outside, any season, in the crowded areas, I get the sensation that there is flushing on the face and neck. what test is advised for me?

anon86141

The ANA test given by the lab here for a patient is 0.37, the ranges being: less than 1 = negative, 1.0 to 1.2; doubtful and greater than 1.2 positive. How do these numbers relate to the titer values of 1 to 10 and increasing dilutions up to, say 400?

anon82385

my ana test did not read. I had it done twice. It was not positive or negative. No antibodies registered, or were seen.

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