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Interpretive Handbook

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Test 61885 :
Antinuclear Antibodies (ANA), IFA with Reflex to Connective Tissue Disease Antibodies

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Antinuclear antibodies (ANA) occur in patients with various autoimmune diseases, both systemic and organ specific, but they are particularly common in systemic rheumatic diseases (SRD). The SRDs include systemic lupus erythematosus (SLE), discoid lupus erythematosus, drug-induced lupus erythematosus, mixed connective tissue disease, Sjogren’s syndrome, scleroderma (systemic sclerosis), CREST syndrome (calcinosis, Raynaud’s phenomenon, esophageal dysmotility, sclerodactyly, telangiectasia), rheumatoid arthritis, and polymyositis or dermatomyositis.

 

Autoantibodies with High Specificity for

Individual Connective Tissue Diseases

dsDNA antibodies

SLE

Scl 70 antibodies (topoisomerase 1)

Scleroderma

Jo 1 antibodies (histidyl tRNA synthetase)

Polymyositis

SSA/Ro and SSB/La antibodies

Sjogren’s syndrome

RNP antibodies (in isolation)

MCTD

Sm antibodies

SLE

Ribosome P antibodies

SLE

 

Low titers of ANA reactivity are observed in approximately 5% of apparently healthy individuals and the incidence increases with increasing age. Titers > or =1:160 are generally considered to be clinically significant and more closely related to the presence of active disease. The results of this test must be interpreted in the context of the clinical picture.

Useful For Suggests clinical disorders or settings where the test may be helpful

Evaluation of patients with signs and symptoms compatible with connective tissue diseases

 

The testing algorithm is useful in the initial evaluation of patients and performs best in clinical situations in which the prevalence of disease is low

Interpretation Provides information to assist in interpretation of the test results

Interpretive comments are provided.

See individual test IDs for additional information.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is a laboratory diagnostic aid and by itself is not diagnostic. Positive results of this test may occur in apparently healthy people. Therefore, the results of this test must be interpreted by a medical authority in the context of the patient's total clinical condition.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

<1:40 (Negative)

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Bradwell AR, Stokes RP, Johnson GD: Atlas of HEp-2 patterns. San Diego, CA. The Binding Site, 1995, pp 9, 10, 19, 38-54

2. Fritzler MJ: Immunofluorescent antinuclear antibody test. In Manual of Clinical Laboratory Immunology. Fourth edition. Edited by NR Rose, EC De Macario. Washington, DC, ASM Press, 1992, pp 724-727

3. McCarty GA, Valencia DW, Fritzler MJ: Antinuclear antibodies. In Contemporary Techniques and Clinical Application to Connective Tissue Diseases. Oxford University Press, Inc, 1984, pp 3

4. Stites DP, Terr AI: Basic and Clinical Immunology. Seventh edition. Edited by DP Stites, AI Terr. Norwalk, CT. Appleton and Lange, 1991, pp 220


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