Scl 70 Antibodies, IgG, Serum

Casandra

Casandra Test Code MC32949Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID SCL70CPT Code 86235

Scl 70 Antibodies, IgG, Serum

Clinical Use

Use

Evaluating patients with clinical features of systemic sclerosis and in the differential evaluation of individuals at-risk for connective tissue disease with Hep-2 substrate antinuclear antibody positive result. Antibody to Scl 70 is considered specific for systemic sclerosis (SSc) and is typically associated with diffuse cutaneous SSc, which is characterized by disease severity including musculoskeletal, cardiac involvement, and interstitial lung disease. It is also associated with a positive antinuclear antibody (ANA) when tested with the HEp-2 substrate using the indirect immunofluorescence assay (IFA). Clinical context and correlation with positive ANA test using HEp-2 is crucial for proper interpretation.

Special Instructions

Testing for Scl70 antibodies is not useful for individuals who test negative for antinuclear antibody using Hep-2 substrate by IFA. Consider further diagnostic evaluation in the presence of a positive ANA test.

Limitations

The presence of Scl 70 antibodies has a high degree of specificity for systemic sclerosis but the assays could show discrepancies due to different detection methods. Discrepancies between anti-Scl-70 antibody assays can impact clinical care, particularly in patients with interstitial lung disease. Low positive Scl 70 antibody results can be present in other inflammatory conditions, such as systemic lupus erythematosus, necessitating cautious interpretation. Performance characteristics of individual assays may vary, with some assays being less specific compared to traditional immunodiffusion methods.

Test Details

New York Approved