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Anti-dsDNA (Double-stranded) Ab by Farr method (RDL)

CPT: 86225
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  • Double Stranded DNA by Farr
  • dsDNA
  • DsDNA Farr
  • Farr
  • Lupus
  • SLE

Expected Turnaround Time

7 - 10 days

Related Documents

Specimen Requirements




1 mL

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)


Red-top tube or gel-barrier tube


Separate serum from cells within one hour of collection. Transfer to a plastic transport tube before shipping. To avoid delays in turnaround time when requesting multiple tests on frozen samples, please submit separate frozen specimens for each test requested.

Storage Instructions

Refrigerate or freeze.

Stability Requirements



Room temperature

7 days


14 days


60 days

Freeze/thaw cycles

Stable x1

Causes for Rejection

Grossly hemolyzed; bacterial contamination; lipemic specimen; icteric specimen; non-serum specimen types

Test Details


The Farr method detects the high-affinity anti-dsDNA antibodies. The Farr assay is the most specific method for detecting dsDNA auto antibodies. Significant elevations in dsDNA autoantibody concentrations confirm the diagnosis of systemic lupus erythematosus (SLE). Serial studies of elevated values of dsDNA auto antibodies are useful for predicting activity of SLE and for measurement of serum C3 or C4 concentrations. Absence of dsDNA autoantibodies does not exclude the diagnosis of SLE. Doubling of dsDNA autoantibody concentrations or increases greater than 30 IU/mL in less than 10 weeks are reliably predictive of exacerbations of SLE. A simultaneous decrease in serum C4 complement enhances this predictive value.


This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.


Radioimmunoassay (RIA) Farr Technique


Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
520059 Anti-dsDNA Ab by Farr (RDL) 47299-3 520060 Anti-dsDNA Ab by Farr(RDL) IU/mL 47299-3

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