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).
- 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
20-39 Units: Weak Positive
40-80 Units: Moderate Positive
81 Units or greater: Strong Positive
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 Name||LOINC|
|2001602||RNA Polymerase III Antibody, IgG||79182-2|
- RNA pol 3
- RNA Pol III IgG
- RNA Polymerase III Ab