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Test Code RNAPSO RNA Polymerase III Antibodies, IgG, Serum

Additional Codes

Mayo Test Code: RNAP

Reporting Name

RNA Polymerase III Ab, IgG, S

Useful 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

Serum


Specimen 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
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

Cautions

A positive result indicates detectable anti-RNA polymerase III above assay cutoff and does not unequivocally establish a diagnosis of systemic sclerosis.(6,7)

 

Enzyme immunoassay to detect anti-RNA polymerase III antibody uses an immunodominant epitope as antigen. Negative result does not also rule out the presence of antibodies targeting other epitopes in the RNA polymerase I/III antigens.

 

The level of RNA polymerase III autoantibodies does not indicate the severity of disease in patients with systemic sclerosis (SSc). However, patients with high positive anti-RNA polymerase III antibody titers are more likely to have SSc compared to those with low antibodies.(7)

 

Anti-RNA polymerase III antibodies may occur prior to clinical onset of SSc.(7)

 

The presence of immune complexes or other immunoglobulin aggregates in the patient specimen may cause an increased level of nonspecific binding and produce false-positive results with this assay.

Report Available

2 to 7 days

Specimen Retention Time

14 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK
Heat-treated specimen Reject

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)