Days Set Up
Monday - Friday
Analytic Time

1 day

MiChart Code
Extractable Nuclear Antibodies, Sm and RnP
Soft Order Code

Test Updated:


Smith Antibody
Anti-Sm (Smith)
RNP Antibody
SmRNP Antibody
U1RNP Antibody
Sm (Smith) Antibody
ENA 3 Antibody Panel
Anti-RNP (Ribonucleoprotein)

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Find a Requisition

All specimens should be accompanied by a requisition.

Submitting Specimens

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Order Kits and Supplies

MLabs provides all the supplies necessary for the collection of specimens.

Test FAQ

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Test Overview

Test Methodology

Multiplex Flow Immunoassay

Test Usage

Antibodies to the Sm antigen represent a highly specific marker for SLE, but only occur in 25 - 35% of patients with the disease. Antibodies to RNP occur in 30 - 40% of patients with SLE, but are not specific for SLE. Antibodies to RNP are present in nearly all patients with Mixed Connective Tissue Disease (MCTD), and are specific for this disorder when all other antibodies are negative. The Sm and RNP antigens are closely associated, part of a protein and small nuclear RNA complex. The Bioplex 2200 ANA screen test system has beads coated with affinity purified Sm, with recombinant antigens RNP-68 and RNP-A, and a separate bead coated with Sm/RNP combined purified antigen.

Reference Range


* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Specimen Requirements

Collection Onsite

Collect specimen in SST tube.

Collection Offsite

Collect specimen in SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate.

Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.25 mL serum

Billing Information

CPT Code
86235 x3
Pro Fee Code
Z260-0 SMRN, 31627-3 SMITH, 31628-1 SMRNP, 8091-1 RNP

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Our High Standard

Quality that sets us apart

As the reference laboratory division of Michigan Medicine's Department of Pathology, MLabs shares the institution's commitment to applying established quality principles to clinical laboratory testing. Like other large organizations in complex, consequential fields, we rely on an established approach to monitor quality throughout the testing process.