RNA Polymerase III Antibody, IgG
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 Systemic Sclerosis Comprehensive Panel (2013325).

Semi-Quantitative Enzyme-Linked Immunosorbent Assay
Tue, Thu, Sun
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
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
Unacceptable Conditions
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year 
Reference Interval
19 Units or lessNegative
20-39 UnitsWeak Positive
40-80 UnitsModerate Positive
81 Units or greaterStrong 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.

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.
  • RNA pol 3
  • RNA Pol III IgG
  • RNA Polymerase III Ab