INDIVIDUAL TEST 024

ANA Specificities

Indication

Antibodies against extractable nuclear antigens (ENA) are important markers for a number of rheumatic systemic diseases.

Sample material

Serum

• Minim. volume: 0,5 mL

Transport

Within Sweden

• room temperature

International

• cold

Method

Immunoblot

Reference interval

Serum

• ≤10 negative

Result

Results are reported as negative or positive with an intensity value. Positive results for Sm, nRNP, SSB, Scl-70 or Jo-1 are confirmed with ELISA.

Interpretation

The presence of anti-nuclear antibodies (ANA) is considered an important finding for diagnosing several different autoimmune diseases. To determine specificity, ENA antibodies are tested which can be directly associated with certain rheumatic systemic diseases as follows:

• Antibodies against Sm antibodies

  are markers for systemic lupus erythematosus (SLE).

• Antibodies against nRNP antibodies

  occur in several rheumatic systemic diseases, such as mixed connective tissue disease (MCTD), systemic lupus erythematosus (SLE) and systemic sclerosis. Anti-nRNP is a diagnosis criterion for MCTD.

• Antibodies against SSA/Ro60 antibodies

  occurs mainly in Sjögren's syndrome and systemic lupus erythematosus (SLE) but can also be seen in other rheumatic systemic diseases. During pregnancy anti-SSA is associated with neonatal lupus.

• Antibodies against SSB (La) antibodies

  occur predominantly in combination with anti-SSA and are seen mainly in primary Sjögren's syndrome and systemic lupus erythematosus. The clinical relevance of isolated anti-SSB antibodies is unclear.

• Antibodies against Scl-70

  are primarily a marker for systemic sclerosis of diffuse type.

• Antibodies against Jo-1

  is a marker for dermatomyositis/polymyositis and is associated with interstitial lung disease ("antisynthetase syndrome").

• Antibodies against SSA/Ro52

  is associated with several autoimmune conditions such as rheumatic diseases, inflammatory myositis and autoimmune liver disease.

During pregnancy, high concentrations of anti-SSA/Ro52 is associated with congenital AV-block/cardiac arrhythmia in the fetus. In women with known SLE/Sjögrens syndrome, the risk of this is estimated to be around 3%. The risk of mothers with these antibodies but without rheumatic disease is unknown but is believed to be lower. For early diagnosis of AV-block weekly monitoring of the fetal heart rhythm is recommended between 18-24 weeks of gestation.

References

• Tomer Y et al. Int Arch Allergy Immunol. 1993. Pathogenic significance and diagnostic value of lupus autoantibodies. PMID: 8481649
• von Mühlen CA, Tan EM. Semin Arthritis Rheum. 1995. Autoantibodies in the diagnosis of systemic rheumatic diseases. PMID: 7604300
• Van Duijnhoven HL et al. Clin Biochem. 1999. A comparison of ELISA assays as routine diagnostic test for detection of autoantibodies against extractable nuclear antigens. PMID: 10383077
• Hiepe F et al. Int Arch Allergy Immunol. 2000. Antinuclear antibody- and extractable nuclear antigen-related diseases. PMID: 11014966
• Mahler M et al. Clin Immunol. 2003. Advances in B-cell epitope analysis of autoantigens in connective tissue diseases. PMID: 12763475
• Hennes EM et al. Hepatology. 2008. Simplified criteria for the diagnosis of autoimmune hepatitis. PMID: 18537184
• Damoiseaux J et al. Ann Rheum Dis. 2019. Clinical relevance of HEp-2 indirect immunofluorescent patterns: the International Consensus on ANA patterns (ICAP) perspective. PMID: 30862649
• Chan EKL et al. LEC; ICAP Committee. The International Consensus on ANA Patterns (ICAP) in 2021-The 6th Workshop and Current Perspectives. J Appl Lab Med. 2022 Jan 5;7(1):322-330. PMID: 34996073.
• Bonroy C et al. Clin Chem Lab Med. 2023 Detection of antinuclear antibodies: recommendations from EFLM, EASI and ICAP. Clin Chem Lab Med. 2023 PMID: 36989417.

Last updated: 2025-01-16