ANA and ENA tests are two blood tests to diagnose autoimmune diseases. An autoimmune disease occurs when the adaptive immune system mistakenly attacks healthy parts of the body. Examples include type 1 diabetes, rheumatoid arthritis, Crohn’s disease, and thyroid conditions.
The key difference between ANA and ENA test is their function. ANA test is a general diagnostic test for autoimmune diseases that measures the amount of antinuclear antibodies in the blood, while ENA test is a more specific diagnostic test for autoimmune diseases that evaluates which proteins in the cell nucleus are recognized by the autoantibodies.
CONTENTS
1. Overview and Key Difference
2. What is ANA Test
3. What is ENA Test
4. Similarities – ANA and ENA Test
5. ANA vs ENA Test in Tabular Form
6. Summary – ANA vs ENA Test
7. FAQ – ANA and ENA Test
What is ANA Test?
An ANA test is a blood test that checks for antinuclear antibodies in a person’s blood. The antinuclear antibody attacks its own healthy cells, so the presence of this autoantibody in the blood can be used to diagnose autoimmune diseases. It’s called “antinuclear” because it targets the nucleus of the cells. This test is used to diagnose lupus, rheumatoid arthritis, scleroderma, Sjögren’s syndrome, Addison disease, and autoimmune hepatitis.
A positive ANA test alone is not enough for a diagnosis of an autoimmune condition. The diagnosis needs the support of an ENA panel. Furthermore, this blood test has very few risks: a small bruise later in the blood-drawn area, dizziness or fainting, bleeding, soreness, and bruising.
What is ENA Test?
ENA is more specific than an ANA test in diagnosing autoimmune diseases. It identifies which specific proteins the body has developed antibodies against. Extractable nuclear antigen antibodies are a group of autoantibodies that target certain proteins and ribonucleoproteins located in the nucleus of the cell nucleus. Some of the common ENA antibodies are anti-Sm (Smith) antibodies, anti-SS-A (Ro) and anti-SS-B (Lo) antibodies, anti-RNP antibodies, scl-70 antibodies, and anti-Jo-1 antibodies. Moreover, the 6-test ENA panel is used to identify mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE), Sjögren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis.
There are minimal risks associated with the ENA test. Some of the side effects may include feeling unpleasant, bruises in the blood-drawn region of the body, and feeling lightheaded or fainting.
Similarities Between ANA and ENA Test
- ANA and ENA tests are used to diagnose autoimmune diseases.
- Both are blood tests.
- These tests detect autoantibodies.
- Both tests are comparatively cheap and cost-effective.
- Both tests have some minor risks.
Difference Between ANA and ENA Test
Definition
- ANA test is a that measures the amount of antinuclear antibodies in the blood.
- ENA test is a test that evaluates which proteins in the cell nucleus are recognized by the autoantibodies.
Type
- ANA is a general screening test for autoimmune diseases.
- ENA test is a specific screening test for autoimmune diseases.
Used to Diagnose
- ANA test can be used to diagnose systematic lupus, rheumatoid arthritis, scleroderma, Sjögren’s syndrome, Addison disease, and autoimmune hepatitis.
- ENA test can be used to diagnose mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE), Sjögren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis.
Risks Associated
- ANA test has few risks, such as a small bruise later in the blood-drawn area, dizziness or fainting, bleeding, soreness, and bruising.
- ENA test has few risks, such as feeling unpleasant, bruises in the blood-drawn region of the body, feeling lightheaded or fainting, and infections.
Cost
- The cost of an ANA test ranges from $11 to $74.
- The cost of an ENA test is approximately $119.
The following table summarizes the difference between ANA and ENA test.
Summary – ANA vs ENA Test
Autoimmune diseases are conditions where the immune system mistakenly damages healthy cells in the human body. Autoimmune conditions can be diagnosed through blood tests. ANA and ENA tests are two blood tests that are used to diagnose autoimmune diseases. ANA test is a general screening test for autoimmune diseases, while ENA tests is a specific screening test for autoimmune diseases. Moreover, ANA test measures the amount of antinuclear antibodies in the blood, whereas ENA test accurately identifies which specific proteins people have antibodies against. This is the summary of the difference between ANA and ENA test.
FAQ: ANA and ENA Test
1. What is the role of autoantibodies?
- Autoantibodies respond to the body’s own proteins, leading to an abnormal immune response that attacks the cells, tissues, and organs of the body and contributes to the development of autoantibody disease or autoimmune disease.
2. What does it mean if the ANA is positive?
- A positive result on an ANA test indicates that antinuclear antibodies were found in the blood of the person. Therefore, a positive result may be a sign of autoimmune diseases like systemic lupus erythematosus (SLE), rheumatoid arthritis, scleroderma, Sjögren’s syndrome, etc.
3. What cancers cause a positive ANA?
- Lung, breast, and colon cancers can sometimes produce positive ANA test results. This is because these cancers can interfere with the normal functioning of the immune system, which can lead to an abnormal autoimmune response.
4. What is an ENA blood test done for?
- An ENA test is used to help diagnose certain autoimmune diseases such as mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE), Sjögren syndrome, scleroderma (systemic sclerosis) and polymyositis/dermatomyositis. ENA tests identify which specific proteins people have antibodies against.
5. What is the ENA test used for?
- An ENA is more specific than an ANA test, and it tells people which specific proteins they have antibodies against. This is a valuable test because sometimes, people without autoimmune diseases can also test positive for an ANA. The test reports will be ready within 24 hours.
Reference:
1. “Antinuclear Antibodies (ANA) Test: Results, Positive vs. Negative, Causes.” WebMD.
2. “Ena Test.” Mayo Clinic, Mayo Foundation for Medical Education and Research.
Image Courtesy:
1. “ANA Immunofluorescence” By Simon Caulton – Own work (CC BY-SA 3.0) via Commons Wikimedia
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