Search our Test Catalog. Specify what to search (name, test code, titles, everywhere) and how to search (begins with, contains)

Unit Code 80178:
Scl 70 Antibodies, IgG, Serum

Print Friendly View
Print Page Email Page

Useful For

Evaluating patients with signs and symptoms of scleroderma and

other connective tissue diseases in whom the test for antinuclear

antibodies (ANA) is positive

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 Diseases Cascade Test-Ordering Algorithm"

in Special Instructions and "Optimized Laboratory Testing for

Connective Tissue Diseases in Primary Care: The Mayo Connective

Tissue Diseases Cascade" in Publications.

Reference Values

<1.0 U (negative)

> or =1.0 U (positive)

 

Reference values apply to all ages.

Interpretation

A positive test result for Scl 70 antibodies is consistent with a

diagnosis of scleroderma.

Cautions

Testing for Scl 70 antibodies is not useful in patients without

demonstrable ANA.

Special Instructions and Forms

• Connective Tissue Diseases Cascade Test-Ordering Algorithm 

Clinical Reference

1.   Homburger H, Larsen S:  Detection of specific antibodies. In

      Clinical Immunology:  Principles and Practice. 1st 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. 2nd edition. Edited by R Rich, T Fleisher, W Shearer,

      et al. St. Louis, Mosby-Year Book, 2001, pp 64.1-64.10

Key