ENA IGG PROFILE (EXTENDED)

ENA IgG Profile (Extended) Tests: Autoantibody Panel and Interpretation

The ENA IgG Profile (Extended) is a highly specialised blood test that serves as a powerful tool for diagnosing and classifying Systemic Autoimmune Rheumatic Diseases (SARDs), also known as Connective Tissue Diseases (CTDs).

ENA stands for Extractable Nuclear Antigens, which are proteins and nucleic acids located within the cell nucleus. In certain autoimmune conditions, these antigens are mistakenly targeted by the body's immune system, leading to the production of IgG autoantibodies.

This single test includes a panel of 18 specific IgG autoantibody tests, providing critical insights into the type of autoimmune disease present, such as Systemic Lupus Erythematosus (SLE), Sjögren's Syndrome, Systemic Sclerosis, and Inflammatory Myositis.

What is the ENA IgG Profile (Extended) Test?

This assay is performed to identify the presence and concentration of IgG-class antibodies directed against a comprehensive panel of 18 specific antigens. The test is typically performed using an advanced method like Immunoblot or Multiplex ELISA.

The ENA profile is most often requested after a patient has received a positive Anti-Nuclear Antibody (ANA) test result, as the ENA profile helps to specify which nuclear antigens are being targeted, thereby determining the patient's specific diagnosis.

What is the ENA IgG Profile (Extended) Test Price?

The ENA IgG Profile (Extended) is a specialised test, and its price is higher than common blood work because it's essentially 18 separate, highly complex tests rolled into one. Here are the main things that affect the final cost:

• High-Tech Testing: The test requires very advanced, expensive machinery and complex chemical processes to accurately check for 18 different antibodies at the same time. This specialised technology ensures your doctor gets precise diagnostic information.
• Where You Live: The cost can change slightly from one city to another, depending on local lab running costs and transportation for the special materials needed.
• Your Service Choice: If you choose the convenience of having a technician come to your home to collect the sample, the total price may be slightly adjusted to cover travel and service charges.
• Quality Assurance: When the test is run at a high-quality, certified lab, it guarantees the results are accurate and reliable, which is crucial for diagnosing serious long-term conditions.

If you are looking for the exact, most up-to-date ENA IgG Profile (Extended) Test price in your area, the simplest way is to check the Apollo 24|7 website or app.

What is the Purpose of the ENA IgG Profile (Extended) Test?

The primary purpose of this extended panel is differential diagnosis and classification of complex systemic autoimmune diseases.
Sub-classifying Autoimmune Disease: A positive ANA test is non-specific. The ENA profile helps distinguish between different CTDs (e.g., separating Lupus from Mixed Connective Tissue Disease) based on the unique signature of autoantibodies detected.

• Prognosis and Monitoring: The presence of certain antibodies can indicate a higher risk for specific organ involvement (e.g., Rib-P0 suggests psychiatric involvement in SLE, Scl-70 suggests lung fibrosis in SSc). Monitoring the titre (level) of certain antibodies (like dsDNA) can occasionally track disease activity.
• Guiding Treatment: Accurate classification is vital because treatment protocols differ significantly between diseases. For example, the treatment for Lupus (SmD1 positive) is different from the treatment for Polymyositis (Jo-1 positive).
• Assessing Risk in Asymptomatic Individuals: In patients with a positive ANA but mild, non-specific symptoms, this panel helps assess the risk of developing a full-blown CTD in the future.

Who Should Get an ENA IgG Profile (Extended) Test Done?

This test is generally recommended by rheumatologists or other specialists for patients who meet the following clinical criteria:

• Positive ANA with Specific Clinical Features: Patients who have a positive ANA screening test and exhibit signs and symptoms suggestive of a systemic autoimmune disease.
• Non-specific Multi-System Symptoms: Individuals presenting with vague, generalised, or multi-system symptoms that are challenging to diagnose, such as:

Unexplained persistent fatigue or fever

Chronic joint pain (arthralgia) or arthritis

• Photosensitive rash (rash triggered by sunlight)
• Raynaud’s phenomenon (fingers/toes turning white or blue in cold)
• Muscle weakness (myositis symptoms)

Unexplained pulmonary (lung) or renal (kidney) involvement

Known CTD Follow-Up: Sometimes used to assess disease progression or monitor the development of secondary syndromes in patients already diagnosed with a CTD.

Components of the ENA IgG Profile (Extended) Test

This specialised diagnostic test quantifies 18 distinct autoantibodies. Identifying the presence of these antibodies helps create a specific "autoantibody profile" for the patient.

• dsDNA (Double-stranded DNA): Highly specific for Systemic Lupus Erythematosus (SLE). Titres often correlate with disease activity, particularly lupus nephritis (kidney involvement).
• Nucleosomes: These are the core particles of chromatin. Antibodies against nucleosomes are often detected earlier than dsDNA and are highly associated with active SLE and lupus nephritis.
• Histones: These structural proteins of chromatin are the primary target in Drug-Induced Lupus, but can also be seen in traditional SLE.
• SmD1 (Smith antigen): The Sm antigen is part of the spliceosome. Antibodies to SmD1 are considered highly specific (diagnostic) for Systemic Lupus Erythematosus (SLE).
• PCNA (Proliferating Cell Nuclear Antigen): Associated with a specific, severe subset of SLE, often involving kidney disease.
  Rib-P0 (Ribosomal P protein): Specific for SLE and strongly associated with neuro-psychiatric lupus (NPSLE), which can manifest as depression, psychosis, or cognitive impairment.
• SS-A/Ro60: An antigen component targeted in Sjogren's Syndrome and SLE. Associated with primary Sjogren's, subacute cutaneous lupus, and Neonatal Lupus (when transmitted to the fetus).
• SS-A/Ro52: The 52 kDa component of the Ro antigen. Often co-exists with SS-A/Ro60. It can be associated with Sjogren's, Myositis, and Scleroderma.
• SS-B/La: Highly specific for Sjogren's Syndrome and usually indicates a high risk of developing the syndrome.
• CENP B (Centromere Protein B): Highly specific for the Limited Cutaneous form of Systemic Sclerosis (SSc), also known as CREST syndrome.
• Scl-70 (Topoisomerase I): Highly specific for the Diffuse Cutaneous form of Systemic Sclerosis (SSc), associated with rapid skin thickening and a higher risk of severe internal organ disease, particularly interstitial lung disease (ILD).
• U1-snRNP (U1 small nuclear ribonucleoprotein): The presence of U1-snRNP is the defining diagnostic criterion for Mixed Connective Tissue Disease (MCTD).
• AMA-M2 (Anti-Mitochondrial Antibody M2): This is the primary diagnostic marker for Primary Biliary Cholangitis (PBC), an autoimmune liver disease. It is included to help differentiate the cause of hepatic involvement when autoimmune disease is suspected.
• Jo-1 (Histidyl-tRNA synthetase): The most common myositis-specific antibody. It is characteristic of Polymyositis and Dermatomyositis and is strongly linked to the development of interstitial lung disease (ILD).
• PM-Scl (Exosome complex): Highly associated with Polymyositis-Scleroderma Overlap Syndrome, where patients exhibit features of both conditions.
• Mi-2 (Chromodomain helicase DNA-binding protein): Specific for classic, acute-onset Dermatomyositis. Often indicates a good prognosis and response to treatment.
• Ku (DNA-dependent protein kinase): Associated with various Overlap Syndromes involving combinations of Myositis, Scleroderma, and SLE features.
• CONTROL BAND: This is an internal quality control marker used by the laboratory to confirm the successful and valid completion of the testing procedure.

Understanding an ENA IgG Profile (Extended) Test Report

The ENA profile report will typically show a result for each of the 18 autoantibodies as either "Negative" (Not Detected), "Positive" (Detected), or sometimes a quantitative value or titre, which indicates the concentration.

Interpreting Test Findings

The interpretation relies on identifying the specific pattern of positive results. It’s important to note that test panels and reporting formats may vary slightly between laboratories. Here’s a typical set of autoantibody findings and their associated medical conditions:

Important Note:

A positive ENA (Extractable Nuclear Antigen) test alone does not confirm a diagnosis. It must be interpreted by a rheumatologist alongside your symptoms, medical history, and other lab results such as complement levels and kidney function. The test is only valid if the control band is positive; a negative control band means the test must be repeated. Additionally, some individuals may initially test negative but develop detectable antibodies later, so follow-up testing may be needed over time.

Preparation and Procedure for ENA IgG Profile (Extended) Test

If you're planning to take the ENA IgG Profile (Extended), here's what you need to know to make the process smooth and get the most accurate results.

1. How is the Test Done?

For the ENA IgG Profile (Extended) Test, a venous blood sample is collected by a trained phlebotomist, typically from a vein in the arm. The sample is then sent to a laboratory where it is analysed using immunoassay techniques to detect and measure specific IgG autoantibodies against extractable nuclear antigens (ENAs).

2. Is Fasting Required for This Test?

No, fasting is NOT required for the ENA IgG Profile.

3. How to Prepare for This Test?

No specific preparation is needed. You may continue all medications as prescribed by your doctor. However, always inform your doctor about any medications you are taking, as some drugs can potentially influence autoimmune activity or the expression of symptoms.

Booking ENA IgG Profile (Extended) Test Online & Checking Reports

A. What are the Steps to Schedule the Test on Apollo 24|7?

• Visit the Apollo 24|7 website or mobile application and search for the ENA IgG Profile (Extended) Test.
• Review the current price and click on the ‘Book Now’ button.
• Select your preferred date and time for a home sample collection.
• Complete the payment process. You will receive confirmation and a booking receipt.

B. How Do I Access My Test Results Online on Apollo 24|7?

• Log in to your Apollo 24|7 account.
• Navigate to the ‘Health Records’ or ‘My Reports’ section.
• Click on the ENA IgG Profile (Extended) Test report to view or download the results in PDF format for sharing with your treating physician/rheumatologist.

Conclusion

The ENA IgG Profile (Extended) is a valuable diagnostic tool that helps rheumatologists understand a patient's autoimmune activity in detail. By detecting specific autoantibodies linked to connective tissue diseases, the test supports accurate disease classification. This clarity enables physicians to tailor treatment plans more effectively, improving care for individuals with complex autoimmune conditions.