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Test ID RNP RNP Antibodies, IgG, Serum


Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Secondary ID

81357

Useful For

Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive

 

Testing for RNP antibodies is not useful in patients without demonstrable antinuclear antibodies.

Testing Algorithm

For more information see Connective Tissue Disease Cascade.

Special Instructions

Method Name

Multiplex Flow Immunoassay

Reporting Name

RNP Ab, IgG, S

Specimen Type

Serum

Specimen Minimum Volume

0.35 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Clinical Information

RNP (also called nRNP and U1RNP) is a small nuclear ribonucleoprotein that contains 3 protein autoantigens (called A, C, and 68 kD). Sera that contain RNP antibodies react predominately with the A and 68-kD autoantigens. Antibodies to RNP occur in approximately 50% of patients with lupus erythematosus (LE) and in patients with other connective tissue diseases, notably mixed connective tissue disease (MCTD). MCTD is characterized by high levels of RNP antibodies without detectable Sm (Smith) or double-stranded DNA (dsDNA) antibodies. MCTD resembles LE but is not accompanied by renal involvement.(1,2)

 

RNP is 1 of 4 autoantigens commonly referred to as extractable nuclear antigens (ENA). The other ENAs are SS-A/Ro, SS-B/La, and Sm. Each ENA is composed of 1 or more proteins associated with small nuclear RNA species (snRNP) ranging in size from 80 to approximately 350 nucleotides. Antibodies to ENAs are common in patients with connective tissue diseases (systemic rheumatic diseases) including LE, MCTD, Sjogren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis.

 

For more information see Connective Tissue Disease Cascade.

Reference Values

<1.0 U (negative)

≥1.0 U (positive)

Reference values apply to all ages.

Cautions

No significant cautionary statements

Day(s) Performed

Monday through Saturday

Report Available

1 to 3 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

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

86235

NY State Approved

Yes