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HelpTest Code RNAP RNA Polymerase III Antibodies, IgG, Serum
Reporting Name
RNA Polymerase III Ab, IgG, SUseful For
Evaluating patients suspected of having systemic sclerosis as part of systemic sclerosis criteria antibody tests
Providing diagnostic and prognostic information in patients with systemic sclerosis
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.3 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Reference Values
<20.0 U (negative)
20.0-39.9 U (weak positive)
40.0-80.0 U (moderate positive)
>80.0 U (strong positive)
Day(s) Performed
Tuesday, Thursday
Test Classification
This test has been cleared, approved, or is exempt by the US 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
83516
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RNAP | RNA Polymerase III Ab, IgG, S | 79182-2 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| RNAP | RNA Polymerase III Ab, IgG, S | 79182-2 |
Interpretation
A positive result for RNA polymerase III antibody may support a diagnosis of systemic sclerosis (SSc) in the appropriate clinical context. Anti-RNA polymerase III autoantibody in patients with SSc is associated with the diffuse cutaneous form of disease and an increased risk of sclerodermal renal crisis.
A negative result indicates no detectable IgG antibodies to RNA polymerase III and does not rule out a diagnosis of SSc. The RNA polymerase III IgG enzyme-linked immunosorbent assay tests only for the RP155 dominant epitope, other epitopes in the antigenic complex are absent and cannot be detected.(6) The overall pooled prevalence of anti-RNA polymerase III antibody is reported to be 11%, 95% CI: 8 to 14, range of 0% to 41% in published studies.(4)
Clinical Reference
1. Stochmal A, Czuwara J, Trojanowska M, Rudnicka L. Antinuclear antibodies in systemic sclerosis: An update. Clin Rev Allergy Immunol. 2020;58(1):40-51
2. Nihtyanova SI, Sari A, Harvey JC, et al. Using autoantibodies and cutaneous subset to develop outcome-based disease classification in systemic sclerosis. Arthritis Rheumatol. 2020;72(3):465-476
3. van den Hoogen F, Khanna D, Fransen J, et al. 2013 classification criteria for systemic sclerosis: an American College of Rheumatology/European League against Rheumatism collaborative initiative. Arthritis Rheum. Arthritis Rheum. 2013;65(11):2737-2747. doi:10.1002/art.38098
4.Sobanski V, Dauchet L, Lefevre G, et al. Prevalence of anti-RNA polymerase III antibodies in systemic sclerosis: New data from a French cohort and a systematic review and meta-analysis. Arthritis Rheumatol. 2014;66(2):407-417. doi:10.1002/art.38219
5. Kuwana M, Kimura K, Kawakami Y. Identification of an immunodominant epitope on RNA polymerase III recognized by systemic sclerosis sera: application to enzyme-linked immunosorbent assay. Arthritis Rheum. 2002;46(10):2742-2747
6. Damoiseaux J, Potjewijd J, Smeets RL, Bonroy C. Autoantibodies in the disease criteria for systemic sclerosis: The need for specification for optimal application. J Transl Autoimmun. 2022;5:100141. doi:10.1016/j.jtauto.202
7. Burbelo PD, Gordon SM, Waldman M, et al. Autoantibodies are present before the clinical diagnosis of systemic sclerosis. PLoS One. 2019;14(3);e0214202
Report Available
2 to 7 daysMethod Name
Enzyme-Linked Immunosorbent Assay (ELISA)