Anti Nuclear Antibody / Factor (ANA / ANF) Test

The Antinuclear Antibody Test is used for the detection of some specific kind of antibodies, called ‘autoantibodies'.

The immune system of your body produces various proteins called antibodies. These antibodies help in detecting any foreign or harmful cells in the body that can cause infections. After detecting these foreign elements, the antibodies go on and destroy these alien cells.

This mechanism of the immune system helps in keeping the body safe against many viruses, bacteria and other disease-causing organisms. However, sometimes the immune system also produces a different kind of antibody, the “autoantibodies.”

These autoantibodies mistakenly identify the body’s own healthy cells as foreign and dangerous cells and go on to destroy them. The proper term for these autoantibodies is antinuclear antibodies (or ANA) because they track the nucleus of the healthy cells and destroy them.

The presence of antinuclear antibodies in the body can be related to many autoimmune disorders like Systemic Lupus Erythematosus and Juvenile Idiopathic Arthritis. However, this only happens when the antinuclear antibodies are present in excess in the body.

The Antinuclear Antibody Test is usually recommended for people who show symptoms of an autoimmune disorder or have already been detected with an immune-mediated health issue.

Systemic Lupus Erythematosus, Juvenile Idiopathic Arthritis, Sjögren’s Syndrome, Polymyositis, Dermatomyositis

Here are some conditions to test for which your doctor may prescribe the Antinuclear Antibody Test:

• Systemic Lupus Erythematosus: This autoimmune disorder is an inflammatory disorder of the immune system and can often be a little difficult to diagnose. The Antinuclear Antibody Test is used for the diagnosis of this disorder as the primary diagnostic test. A high level of antibodies along with a speckled pattern can often be related to this disorder.
• Raynaud’s Phenomenon: In this disorder, the fingers, ears, toes and tip of the nose are commonly involved. These areas of the body often feel numb and cool in response to stress or cold temperatures. Doctors suggest the Antinuclear Antibody Test as one of the first diagnostic tests for this disorder.
• Autoimmune Hepatitis: This autoimmune disease is the cause of a condition wherein the antinuclear antibodies attack the person’s liver. The Antinuclear Antibody Test is used in the diagnosis of Autoimmune Hepatitis when the liver starts showing signs of dysfunction

Apart from these medical conditions, people with any of the following symptoms are also advised to take the ANA Test:

• Tiredness
• Persistent or recurring fever
• The appearance of a butterfly-shaped red rash on the cheeks and bridge of the nose
• Muscle and joint pain
• Swelling and stiffness
• Sensitivity to light
• No sensation or numbness and tingling in the hands or feet

Your healthcare practitioner will recommend you to go for the Antinuclear Antibody Test only if they observe certain symptoms that can be indicative of an autoimmune disorder. This test is not intended to be a part of a routine health checkup.

Before the Test

Normally, no special test preparation is necessary before undergoing an ANA test. However, if this test is conducted along with another test, your physician may advise you to abstain from certain foods. To ensure the most accurate results, seek guidance from a healthcare professional before proceeding with the test.

During the Test

A blood sample is procured from a vein in your arm. Your experience will unfold as follows:

• The area where the needle will be inserted will be sanitised with antiseptic lotion.
• A tourniquet band will be secured around the arm to expand the veins.
• A new syringe needle will be introduced into the vein to extract blood. This process may take a few moments, during which you may experience slight discomfort from the needle pricking.
• The blood sample will be preserved in a small vial or test tube along with your test particulars.

After the Test

Once the blood has been collected:

• A dressing will be applied to the needle insertion site to prevent bleeding.
• In some instances, minor soreness or dizziness may occur. You may be instructed to rest for a few minutes.
• Notify your physician if there is any bleeding, pain, or rash at the puncture site.

The Antinuclear Antibody Test procedure is performed to get information on two specific parameters: the level, which is also called the ‘titer’ of antinuclear antibodies present in the blood and the pattern in which the antinuclear antibodies have been found in the blood sample.

Antinuclear Antibody ‘Titer’ or Level

The titer or level of the ANA test provides an estimation of the number of antinuclear antibodies present in the blood.

To check this level of ANAs, a blood sample is taken. This serum from blood is separated, which is then mixed with a liquid to perform the test for ANA.

If ANA antibodies are present this sample is tested again and again in different ratios of the blood sample and a chemical liquid. Every time one ratio shows the presence of antinuclear antibodies, a new and stronger solution is prepared (in a different ratio than the previous one) and the test for the presence of antinuclear antibodies is conducted again.

If antinuclear antibodies are present even at the strongest ratio or the strongest solution made after mixing the blood sample and the chemical liquid, this indicates that there is a very high number of antibodies in the person’s blood sample.

Antinuclear Antibody Pattern

There are several possible patterns in which antinuclear antibodies can be found in the blood sample. These patterns are also called the ANA staining patterns, which are the patterns in which the antinuclear antibodies stain the blood sample when a chemical is added to the blood sample for testing.

It is established that these staining patterns are loosely related to the underlying autoimmune disease (if any) that these ANAs can cause in a person.

The possible patterns are:

• Homogenous pattern
• Speckled pattern
• Nucleolar
• Centromere

Out of the following, the homogenous staining pattern is considered to be the most common and also the least concerning pattern (or least harmful) of antinuclear antibodies.

This table is meant to guide you in understanding what the different test results mean and how they should be interpreted:

ANA Negative Test Result

With no presence of antinuclear antibodies detected in your blood, you are less likely to develop or have an autoimmune disorder. However, if you have any other symptoms, your doctor may suggest some other tests that detect the presence of other antibodies.

Having an Antinuclear Antibody negative test result does not guarantee that you don’t have autoimmune diseases.

ANA Positive Test Result

The laboratory test results will also inform you of the titer (or level) of the antinuclear antibodies found in your blood sample. The titer may be as follows:

• 1:40
• 1:80
• 1:160
• 1:320
• 1:640

1:40 is the least level of ANA and it increases as you progress in the ratios. So, you can relate 1:640 with the highest amount of ANA present. The staining pattern (as explained in the test parameters) will also be mentioned in the lab ANA test report.

Having an Antinuclear Antibody positive test result is not a confirmation of an autoimmune disease. Many people with antinuclear antibodies present in their bodies still do not have any autoimmune diseases.

However, if you have any symptoms in addition to having a positive ANA test result, your doctor will prescribe additional diagnostic tests.

You can also get a false-positive test result, especially if you are a female above 65 years of age, have an infection like tuberculosis or regularly take blood pressure or anti-seizure drugs.