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Double-Stranded DNA (dsDNA) Farr Assay

Published: July 27, 2026Updated: August 25, 2026

The dsDNA Farr assay measures the levels of double-stranded DNA antibodies in the blood, which are indicative of autoimmune conditions such as systemic lupus erythematosus (SLE).

Quick summary

The dsDNA Farr assay is used to diagnose and monitor autoimmune diseases like lupus.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 25, 2026Editorial policy

Key facts at a glance

Units
IU/mL
Clinical utility
diagnostic
Result kind
quantitative
FDA-cleared
Roche Farr B, Amersham Farr B
interpretation: {"text":"Levels within the reference range (0–10 IU/mL) are generally considered normal and indicate a low likelihood of autoimmune disease.","label":"Low Levels"}; {"text":"Levels above 10 IU/mL may suggest the presence of an autoimmune disorder such as SLE, requiring further diagnostic workup.","label":"High Levels"}

The dsDNA Farr assay is a diagnostic test that quantifies the concentration of double-stranded DNA antibodies in the blood. These antibodies are characteristic of autoimmune disorders, particularly systemic lupus erythematosus (SLE).

The reference range for this biomarker is 0–10 IU/mL. Elevated levels beyond this range may indicate the presence of an autoimmune condition, necessitating further clinical evaluation.

This test is crucial for diagnosing SLE and for monitoring disease activity and treatment effectiveness in affected individuals.

Frequently asked questions

What is the dsDNA Farr assay used for?
It is primarily used to diagnose and monitor systemic lupus erythematosus (SLE) and other autoimmune conditions.
What do high levels of dsDNA antibodies mean?
High levels may indicate an autoimmune disorder like SLE, prompting additional tests and clinical evaluation.
  1. 1
    Clinical Utility of Anti-dsDNA AntibodiesSource
  2. 2
    Lupus Foundation of America: Understanding Laboratory TestsSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy