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RNA Polymerase III Antibody, IgG
2001601
Ordering Recommendation

Recommended first-line test for the evaluation of systemic sclerosis, or connective tissue disease with renal or cutaneous involvement. Panel is available, refer to 2013325.

Mnemonic
RNA POL 3
Methodology
Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Performed
Tue, Thu, Sun
Reported
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum separator tube. 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL) 
Storage/Transport Temperature
Refrigerated. 
Unacceptable Conditions
 
Remarks
 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year 
Reference Interval
19 Units or less: Negative
20-39 Units: Weak Positive
40-80 Units: Moderate Positive
81 Units or greater: Strong Positive
Interpretive Data
The presence of RNA polymerase III IgG antibodies is considered diagnostic of systemic sclerosis (SSc). RNA polymerase III IgG antibodies occur in about 11-23 percent of SSc patients, and typically in the absence of anti-centromere and anti-Scl-70 antibodies. The presence of RNA polymerase III IgG antibodies may be predictive of an increased risk of skin involvement and hypertensive renal failure associated with the diffuse cutaneous form of SSc.

A negative result indicates no detectable IgG antibodies to the dominant antigen of RNA polymerase III and does not rule out the possibility of SSc. False-positive results may also occur due to non-specific binding of immune complexes. Strong clinical correlation is recommended.

If clinical suspicion remains, consider additional testing for other antibodies associated with SSc, including centromere, Scl-70, U3-RNP, PM/Scl, or Th/To.

Note
CPT Code(s)
83516
Components
Component Test Code*Component Chart NameLOINC
2001602RNA Polymerase III Antibody, IgG79182-2
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • RNA pol 3
  • RNA Pol III IgG
  • RNA Polymerase III Ab