RNP Antibody

What the laboratory says this test is for

This panel can be helpful in the diagnosis and management of systemic lupus erythematosus (SLE). The panel simultaneously tests for antinuclear antibodies (ANAs) with an immunofluorescence assay (IFA), performed on human epithelial type 2 (HEp-2) cells, as well as 6 specific autoantibodies associated with SLE and 3 biomarkers associated with disease activity. For specimens with positive ANA IFA results, reflex testing for ANA titer and pattern is performed.The ANA testing has high sensitivity (97%) for SLE but limited specificity (34%) [1]. Anti-dsDNA and anti-Sm antibodies are less sensitive but more specific; tests for both antibodies are included in classification criteria for SLE [2]. Anti-chromatin antibodies have relatively high sensitivity and specificity. Although antibodies to SSA and SSB may also be seen in Sjogren Syndrome and anti-RNP is a marker of mixed connective tissue disease, these antibodies are also frequently present in SLE and may be helpful.The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.References1. Petri M, et al. Arthritis Rheum. 2012;64(8):2677-2686.2. Aringer M, et al. Ann Rheum Dis. 2019;78(9):1151-1159.

What the laboratory says this test is for

This panel can be helpful in the diagnosis of systemic rheumatic disorders and other autoimmune diseases. Although the test for antinuclear antibodies (ANA) is strongly associated with systemic lupus erythematosus (SLE), the laboratory evaluation for individuals with clinical suspicion of a variety of autoimmune diseases often begins with an ANA screen. This panel simultaneously tests for ANA (using immunofluorescence) as well as the important specific autoantibodies associated with a positive ANA. It also includes testing for complement proteins, rheumatoid arthritis, Sjogren's syndrome, systemic sclerosis, polymyositis, anti-phospholipid antibody syndrome, and autoimmune thyroid disease.

What the laboratory says this test is for

This panel can be helpful in the diagnosis of individuals with clinical suspicion of mixed connective tissue disease (MCTD). All specimens are tested for antinuclear antibodies (ANAs) with an immunofluorescence assay (IFA), performed on human epithelial type 2 (HEp-2) cells; and RNP antibodies with a multiplex immunoassay. For specimens with positive ANA IFA results, reflex testing for ANA titer and pattern is performed.The laboratory evaluation for individuals with clinical suspicion of autoimmune diseases often begins with an ANA screen. The classic ANA IFA on HEp-2 cells is considered by the American College of Rheumatology (ACR) as the current gold standard because of its overall high sensitivity for several autoimmune diseases [1]. Knowing the ANA titer and fluorescent staining pattern can be helpful in interpreting positive results [2]. The first indication of MCTD is often a high ANA titer (>1:1000), which occurs in 94% to 97% of patients with MCTD [3]. The presence of RNP antibodies is considered the serologic hall mark of MCTD and required by diagnostic criteria [3].Individuals with negative results on the ANA IFA usually also have negative results on specific autoantibodies. Therefore, subserology testing is not recommended for individuals without positive ANA IFA results and clinical suspicion of relevant autoimmune disease [4]. However, Jo-1 antibody may be detected in ANA IFA-negative patients with some types of myositis, and SSA antibody may be detected in some ANA IFA-negative patients with lupus or Sjogren syndrome [4].The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.References1. Methodology of testing for antinuclear antibodies (position statement). 2009. American College of Rheumatology. Updated December 2019. Accessed May 15, 2023. https://assets.contentstack.io/v3/assets/bltee37abb6b278ab2c/blta48818378bc89445/acr-position-statement-methodology-testing-antinuclear-antibodies.pdf2. Tozzoli R, et al. Am J Clin Pathol. 2002;117(2):316-324.3. Cappelli S, et al. Semin Arthritis Rheum. 2012;41(4):589-598.4. Yazdany J, et al. Arthritis Care Res (Hoboken). 2013;65(3):329-339.

What the laboratory says this test is for

A subset of interstitial lung disease (ILD) patients have underlying connective tissue diseases (CTDs). This panel serves as an aid for the diagnosis of CTDs, including rheumatoid arthritis, inflammatory myositis, systemic sclerosis, and Sjogren’s syndrome, that are associated with the development of ILD. If left untreated, these CTD patients may develop lung fibrosis and inflammation. ILD is a direct consequence of these pathological changes. When severe, ILD leads to restrictive lung disease, pulmonary arterial hypertension, and cardiac disease (cor pulmonale).

What the laboratory says this test is for

RNP Antibodies have been associated with Mixed Connective Tissue disease.