Anti dsDNA Antibody Test – Purpose, Procedure, and Normal Range

Overview

The Anti-dsDNA Antibody Test is a blood test that detects antibodies against double-stranded DNA (dsDNA) — the genetic material found inside our own cells.
These antibodies are called autoantibodies because they target the body’s own tissues instead of harmful microbes.

This test is highly specific for Systemic Lupus Erythematosus (SLE), an autoimmune disorder where the immune system attacks healthy organs and tissues.
Doctors use this test to diagnose lupus, monitor disease activity, and predict lupus flares, particularly when the kidneys are involved (a condition known as lupus nephritis).

What Is the Anti-dsDNA Antibody Test?

The Anti-dsDNA (Anti–Double-Stranded DNA) Test measures the presence of autoantibodies that mistakenly attack double-stranded DNA molecules within the body.

These antibodies are almost exclusive to Systemic Lupus Erythematosus (SLE), meaning that if they are detected, it is strong evidence of lupus.
They are part of a group known as antinuclear antibodies (ANA) — antibodies that react against components of the cell nucleus.

Doctors usually order the Anti-dsDNA test after a positive ANA test to confirm or support a diagnosis of lupus.

Where Are Anti-dsDNA Antibodies Produced?

Anti-dsDNA antibodies are produced by B lymphocytes (B cells) — specialized immune cells that create antibodies.
In autoimmune conditions like lupus, these cells become overactive and misinterpret double-stranded DNA from dying or damaged cells as a threat.

These antibodies are mainly produced in:

• Lymph nodes
• Spleen
• Bone marrow

Once formed, these antibodies circulate in the bloodstream and bind to DNA, forming immune complexes that can get trapped in various organs — particularly the kidneys — leading to inflammation and damage.

Main Functions and Clinical Importance

Anti-dsDNA antibodies have no useful function in a healthy body.
However, their presence and level are clinically important for diagnosis and disease management in lupus.

Clinical Importance:

1. Diagnosis:
   Anti-dsDNA is one of the most specific markers for Systemic Lupus Erythematosus (SLE).
   A positive test almost always points to lupus, especially if accompanied by other clinical symptoms.
2. Monitoring Disease Activity:
   Antibody levels often rise before lupus flare-ups, helping doctors detect disease activity early.
3. Prognosis:
   High Anti-dsDNA levels may signal kidney involvement (lupus nephritis) or a more severe disease form.
4. Differentiation:
   Helps differentiate lupus from other autoimmune diseases, as Anti-dsDNA is rarely found outside of SLE.

Causes of Low or Negative Levels

Low or negative Anti-dsDNA antibody levels usually mean:

• No autoimmune reaction against DNA.
• Lupus is in remission (inactive phase).
• Disease is in early stages before antibody production starts.
• Successful treatment has reduced antibody levels.

In short, a negative result generally rules out active lupus, although some patients with lupus may still have negative Anti-dsDNA results (seronegative lupus).

Symptoms of Low Levels

Low or negative antibody levels themselves cause no symptoms.
However, lupus symptoms may still occur if the disease is active but antibodies are temporarily undetectable.

Causes of High Anti-dsDNA Levels

Elevated Anti-dsDNA antibodies are most commonly seen in Systemic Lupus Erythematosus (SLE).
Other rare causes include certain autoimmune diseases and chronic conditions.

Common Causes:

• Systemic Lupus Erythematosus (SLE) – Primary and most frequent cause
• Mixed connective tissue disease (MCTD)
• Sjögren’s syndrome
• Autoimmune hepatitis
• Drug-induced lupus (caused by certain medicines like hydralazine, procainamide, or isoniazid)
• Chronic infections (rarely)

Symptoms of High Levels

High Anti-dsDNA levels are closely linked to active lupus and can correlate with the severity of symptoms.
Common signs and symptoms include:

• Joint pain, stiffness, and swelling
• Fatigue and low-grade fever
• Skin rash, particularly the malar (butterfly) rash across the cheeks and nose
• Sensitivity to sunlight
• Hair loss (alopecia)
• Mouth or nose ulcers
• Kidney involvement (lupus nephritis) – indicated by:
  • Swelling in legs, ankles, or around eyes
  • Foamy or dark-colored urine
  • High blood pressure
• In severe cases:
  • Inflammation in the heart or lungs (causing chest pain or breathlessness)
  • Nervous system involvement (headaches, confusion, or seizures)

Reference Ranges

(Values may vary by laboratory and testing method — such as ELISA, Farr assay, or Crithidia luciliae assay)

Some laboratories report results simply as Negative / Equivocal / Positive without numeric values.
Results must always be interpreted alongside clinical symptoms and other test findings (like ANA and complement levels).

Sample Type and Test Method

• Sample Required: Serum (blood sample)
• Tube Type: Serum Separator Tube (SST / Red Top)
• Testing Methods:
  • ELISA (Enzyme-Linked Immunosorbent Assay) – Common and reliable
  • Crithidia luciliae immunofluorescence – Highly specific for lupus
  • Farr radioimmunoassay – Used for precise quantitative measurement

The doctor chooses the test type based on required accuracy and clinical situation.

Test Preparation

• No fasting required.
• Inform your doctor about any medications, especially steroids, immunosuppressants, or biologics, which can affect antibody levels.
• The test may be repeated periodically to monitor lupus activity and treatment effectiveness.
• Doctors often order Anti-dsDNA along with:
  • ANA Test
  • Complement (C3, C4) levels
  • Urine protein test (for kidney health)

When to Consult a Doctor

Consult a rheumatologist or physician if you experience:

• Persistent joint pain, swelling, or stiffness
• Unexplained fatigue or fever
• Rashes that worsen with sunlight exposure
• Swelling in legs or face
• Foamy urine or kidney pain
• Family history of autoimmune diseases

Your doctor may order this test if lupus or another autoimmune disorder is suspected based on your symptoms and ANA test results.

Important Word Explanations

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