Anti-dsDNA (Double-Stranded) Antibodies

Anti-dsDNA (Double-Stranded) Antibodies

Number
	096339
CPT
	86225
Synonyms
	Antinative DNA; Anti-N-DNA
Test Includes
	Semiquantitative result of IgG class antibody
Specimen
	Serum
Volume
	1 mL
Minimum Volume
	0.5 mL (Note: This volume does not allow for repeat testing.)
Container
	Red-top tube or serum gel tube
Storage Instructions
	Maintain specimen at room temperature.
Causes for Rejection
	Hemolysis; icterus; lipemia; bacterial contamination
Reference Interval
	Negative: 0-99 U/mL Equivocal: 100-120 U/mL Positive: >120 U/mL
Use
	Specific assay for confirming the diagnosis of systemic lupus erythematosus (SLE)
Limitations
	Low antibody levels may be found in other connective tissue diseases.
Methodology
	Multiplex bead flow cytometry
Additional Information
	Antibodies to DNA, either single or double-stranded, are found primarily in systemic lupus erythematosus, and are important, but not necessary or sufficient for diagnosing that condition. Such antibodies are present in 80% to 90% of SLE cases. They are also present in smaller fractions of patients with other rheumatic disorders, and in chronic active hepatitis, infectious mononucleosis, and biliary cirrhosis. In the past it was considered unnecessary to test for anti-DNA in patients with a negative test for antinuclear antibodies. A group of "ANA negative lupus" patients has been described with anti-ssDNA and anti-SS- A/Ro and anti-SS-B/La. However, HEp-2 substrate is much more sensitive than frozen section substrates, and it is uncommon for anti-SS-A/Ro to be negative with these newer substrates. This standard dsDNA detects both low- and high-affinity antibodies, providing a very sensitive test for diagnostic purposes; however, it is less predictive for severe nephritis, which is associated with the presence of high-affinity antibodies. Following levels of anti-DNA antibody may be of use in evaluating response to therapy, but should be regarded as a guide rather than a rigid dictator of treatment. Antibody levels correlate particularly well with activity of lupus nephritis. Procainamide and hydralazine may induce anti-DNA antibodies, and antihistone antibodies.