Test Code ADNA1 Double-Stranded DNA (dsDNA) Antibodies, IgG, Serum

Specimen Required

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.3 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.

Useful For

Evaluating patients with clinical features or at-risk for systemic lupus erythematosus (SLE)

Monitoring disease activity, as an adjunct test, in patients with SLE previously positive for double-stranded DNA IgG antibodies

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

dsDNA Ab, IgG, S

Specimen Type

Serum

Specimen Minimum Volume

See Specimen Required

Specimen Stability Information

Specimen Type	Temperature	Time	Special Container
Serum	Refrigerated (preferred)	21 days
	Frozen	21 days

Reject Due To

Gross hemolysis	OK
Gross lipemia	OK
Gross icterus	OK

Clinical Information

Systemic lupus erythematosus (SLE) is a chronic autoimmune condition in which an inflammatory immune response leads to damage of a variety of organ systems, including the skin, joints, kidney, vasculature, lungs, and brain. In 2019, the European League Against Rheumatism/American College of Rheumatology published classification criteria for SLE,(1) which includes antibodies to double-stranded DNA (dsDNA) as an SLE-specific autoantibody within the immunology domain. Anti-dsDNA antibodies are also included in the Systemic Lupus International Collaborating Clinics classification criteria (SLICC) for SLE.(2) Detection of IgG antibodies to dsDNA is the most clinically useful isotype.(3-5) The diagnostic performance of dsDNA IgG antibodies in SLE is variable and dependent on several factors, including the immunological method used for their detection, the structure of the DNA antigen, the patient's disease state (early or active vs inactive), and specific clinical manifestations and patient demographics.(3-7) Weak-positive dsDNA IgG antibodies having low affinity and low avidity display variable clinical correlations with SLE.(3)

Testing for IgG antibodies to dsDNA is indicated in patients with clinical features compatible with SLE who are positive for anti-cellular antibody (antinuclear antibody: ANA), particularly the homogeneous pattern identified using HEp-2 substrate by indirect immunofluorescence assay (IFA).(1,2,8) A minority of SLE patients may test negative using HEp-2 by IFA for nuclear antibodies.(8,9) For patients with features of neuropsychiatric disease, testing for antibodies associated with HEp-2 IFA cytoplasmic patterns such as ribosomal P IgG autoantibodies may be useful. In addition, some patients may benefit from testing for additional markers, including Smith, ribonucleoprotein, SSA-52, and SSA-60 antibodies.(8,9)

The reactivity of antibodies to dsDNA may fluctuate with SLE disease activity. Increasing reactivity may be associated with flares while a decline or seronegativity may indicate response to treatment or disease remission.

For more information see First-Line Screening for Autoimmune Liver Disease Algorithm.

Reference Values

<100 IU/mL (negative)

≥100 IU/mL (positive)

Negative is considered normal.

Reference values apply to all ages.

Interpretation

A positive result for double-stranded DNA (dsDNA) IgG antibodies in the appropriate clinical context is suggestive of systemic lupus erythematosus (SLE). The performance characteristics of dsDNA IgG antibodies in SLE is dependent on the immunological method used for their detection, the patient's disease state including clinical manifestations, and demographics.

Weak-positive dsDNA IgG antibody results have a low-positive predictive value for SLE.

Negative results do not rule out a diagnosis of SLE.

Cautions

Measurements of IgG antibodies to double-stranded DNA (dsDNA) are semiquantitative. Slight changes in reactivity of these antibodies should not be relied upon to predict changes in the clinical course of patients with systemic lupus erythematosus (SLE). Clinical flares of disease in patients with SLE may not be accompanied by changes in the reactivity of dsDNA antibodies. Thus, anti-dsDNA antibody results alone are not sufficient to guide disease management.

False-positive results are usually of low titers.

A negative result does not exclude a diagnosis of SLE.

Anti-dsDNA results at or around the reference interval may not correlate with a diagnosis of SLE. Confirmation with Crithidia luciliae indirect immunofluorescence test, which is more specific for SLE, may be useful to establish or exclude the diagnosis in certain circumstances.

Method Description

The test kit contains 12 microtiter strips each with 8 break-off reagent wells coated with double-stranded DNA (dsDNA). In the first reaction step, diluted patient samples, calibrators and controls are incubated in the wells. Anti-dsDNA antibodies will bind to the antigens coated in the microtiter wells. The wells are washed to remove any unbound proteins and non-specific antibodies. In a second reaction step, rabbit anti-human IgG-HRP enzyme conjugate is added to each well. The enzyme conjugate will bind to any wells that have human IgG binding to the dsDNA antigen. The wells are washed to remove any unbound HRP enzyme conjugate. 3,3,5,5, tetramethylbenzidine (TMB) enzyme substrate is added. If the HRP enzyme is present in the well (positive reaction), the HRP enzyme will react with the TMB substrate and produce a blue color. After an additional incubation time to allow the color development, a stop solution is added which turns the blue color yellow and inhibits further color development to allow for stable spectrophotometric reading. The test strips are placed in a microplate reader and the optical density of the color is measured. The amount of antigen specific bound antibody is proportional to the color intensity.(Package insert: Anti-dsDNA-NcX ELISA (IgG). EUROIMMUN; 7/8/2020)

Day(s) Performed

Monday through Saturday

Report Available

2 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86225

LOINC Code Information

Test ID	Test Order Name	Order LOINC Value
ADNA1	dsDNA Ab, IgG, S	33799-8

Result ID	Test Result Name	Result LOINC Value
ADNA1	dsDNA Ab, IgG, S	33799-8

Testing Algorithm