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Test Code SCL70 Scl 70 Antibodies, IgG, Serum

Reporting Name

Scl 70 Ab, IgG, S

Useful For

Evaluating patients with signs and symptoms of scleroderma and other connective tissue diseases in whom the test for antinuclear antibodies is positive

Testing Algorithm

See Connective Tissue Disease Cascade (CTDC) in Special Instructions.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

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

Reference Values

<1.0 U (negative)

≥1.0 U (positive)

Reference values apply to all ages.

Day(s) and Time(s) Performed

Monday through Saturday; 4 p.m., Sunday; 11a.m.

Test Classification

This test has been cleared or approved by the U.S. 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

86235

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SCL70 Scl 70 Ab, IgG, S 47322-3

 

Result ID Test Result Name Result LOINC Value
SCL70 Scl 70 Ab, IgG, S 47322-3

Clinical Information

Scl 70 (topoisomerase 1) is a 100-kD nuclear and nucleolar enzyme. Scl 70 antibodies are considered to be specific for scleroderma (systemic sclerosis) and are found in up to 60% of patients with this connective tissue disease. Scl 70 antibodies are more common in patients with extensive cutaneous involvement and interstitial pulmonary fibrosis, and are considered a poor prognostic sign.(1,2)

 

See Connective Tissue Disease Cascade (CTDC) in Special Instructions.

Interpretation

A positive test result for Scl 70 antibodies is consistent with a diagnosis of scleroderma.

Clinical Reference

1. Homburger H, Larsen S: Detection of specific antibodies. In Clinical Immunology: Principles and Practice. First edition. Edited by R Rich, T Fleisher, B Schwartz, et al. St. Louis, Mosby-Year Book, Inc, 1996, pp 2096-2109

2. White B: Systemic sclerosis. In Clinical Immunology Principles and Practice. Second edition. Edited by R Rich, T Fleisher, W Shearer, et al. St. Louis, Mosby-Year Book, 2001, pp 64.1-64.10

Analytic Time

1 day

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross OK

Other

NA

Method Name

Multiplex Flow Immunoassay