Lab Test

Myositis Autoantibodies

PL-7, PL-12, Mi-2, Ku, EJ, OJ, SRP, Jo-1 , Quest #3242, EPIC: LAB6501, SOFT: XMA

Specimen Collection Criteria

Collect: Two plain Red-top tubes.

Physician Office/Drawsite Specimen Preparation

Let specimen clot 30-60 minutes then centrifuge to separate serum from cells within four hours of collection. Transfer serum to two plastic transport tubes and refrigerate (2-8°C or 36-46°F).

Preparation for Courier Transport

Transport: 6.0 mL serum, refrigerated (2-8°C or 36-46°F). (Min: 2.0 mL)

Rejection Criteria

  • Gross hemolysis and lipemia.
  • Gross Icteric specimens.
  • Specimens not collected and processed as indicated.


Tuesday - Thursday.
Results available in 2-6 days.

Reference Range

PL-7 Autoantibodies: None Detected.
PL-12 Autoantibodies: None Detected.
MI-2: Autoantibodies: None Detected.
KU Autoantibodies: None Detected.
EJ Autoantibodies: None Detected.
OJ Autoantibodies: None Detected.
SRP Autoantibodies: None Detected.
Jo-1 Autoantibodies: Less than 1.0.

Test Methodology

Radioimmunprecipitation Assay/Enzyme Immunoassay.

Clinical Utility

A high proportion of patients with idiopathic inflammatory myopathies (IIMs) which include polymyositis, dermatomyositis and myositis associated with other rheumatic diseases, have autoantibodies directed against aminoacyl-transfer RNA (tRNA) synthetases (myositis-specific antibodies), which are a group of cellular enzymes that catalyze the binding of one amino acid to its tRNA. Autoantibodies to eight of these synthetases, histidyl (Jo-1), threonyl RS (PL-7), alanyl RS (PL-12), isoleucyl RS (OJ), glycyl RS (EJ), leucyl RS, lysyl RS and GluPro RS are reported in IIMs. Histidyl-tRNA synthetase (Jo-1) antibodies are the most common (20-30% of IIMs). Anti-PL-7 and PL-12 are found in 3%, anti-EJ occur in 3%, OJ occur in 2%, and anti-GluPro RS, leucyl RS and lysyl RS occur in less than 1%. Aminoacyl-tRNA synthetase autoantibodies are strongly also associated with interstitial lung disease (ILD), arthritis and Raynaud phenomenon.

CPT Code

83516x5, 86235x3.

Test Codes

Quest #3242, EPIC: LAB6501, SOFT: XMA

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This directory currently reflects information only for specimens collected and/or processed at the
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