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Anti-dsDNA Ab by Farr; C3 & C4 Complements; Anti-C1Q Ab, IgG
14 - 21 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
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.
Refrigerate or freeze.
Grossly hemolyzed; bacterial contamination; lipemic specimen; icteric specimen; non-serum specimen types
Serial testing shows that increasing amounts of IgG anti-C1q predict renal flares in SLE patients. Elevated serum titers of anti-C1q antibodies tend to be associated with proliferative forms of lupus, glomerulonephritis and subendothelial deposits of immune complexes.
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 auto antibodies does not exclude the diagnosis of SLE. Doubling of dsDNA auto antibody 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 ths predictive value. Measurement of C3 is used to detect individuals with inborn deficiency of this factor or those with immunologic disease in whom complement is consumed at an increased rate. These include lupus erythematosus, chronic active hepatitis, certain chronic infections, post-streptococcal and membranoproliferative glomerulonephritis, and others.
Measurement of C4 in serum is used to detect individuals with inborn deficiency of this factor or those with immunologic disease in whom complement is consumed at an increased rate. These include lupus erythematosus, chronic active hepatitis, certain chronic infections, post-streptococcal and membranoproliferative glomerulonephritis, and others.
This test was developed and its performance characteristics determined by LabCorp. It has not been cleared or approved by the Food and Drug Administration.
Enzyme-linked immunosorbent assay (ELISA), RIPA, Enzyme Immunoassay (EIA)
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