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HelpTest ID JO1 Jo 1 Antibodies, IgG, Serum
Reporting Name
Jo 1 Ab, IgG, SUseful For
Evaluating patients with signs and symptoms compatible with a connective tissue disease, especially those patients with muscle pain and limb weakness, concomitant pulmonary signs and symptoms, Raynaud phenomenon, and arthritis
Testing for antibodies to Jo 1 is not useful in patients with a negative test for antinuclear antibodies
Testing Algorithm
For more information see Connective Tissue Disease Cascade.
Specimen Type
SerumSpecimen 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.
Specimen Minimum Volume
0.35 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 21 days |
Special Instructions
Reference Values
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Day(s) Performed
Monday through Saturday
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
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| JO1 | Jo 1 Ab, IgG, S | 33571-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| JO1 | Jo 1 Ab, IgG, S | 33571-1 |
Clinical Information
Jo 1 (histidyl tRNA synthetase) is a member of the amino acyl-tRNA synthetase family of enzymes found in all nucleated cells. Jo 1 antibodies in patients with polymyositis bind to conformational epitopes of the enzyme protein and inhibit its catalytic activity in vitro.(1)
Jo 1 antibodies are a marker for the disease polymyositis, and occur most commonly in myositis patients who also have interstitial lung disease. The antibodies occur in up to 50% of patients with interstitial pulmonary fibrosis and symmetrical polyarthritis.(2)
For more information see Connective Tissue Disease Cascade.
Interpretation
A positive result for Jo 1 antibodies is consistent with the diagnosis of polymyositis and suggests an increased risk of pulmonary involvement with fibrosis in such patients.
Cautions
A negative test for Jo 1 antibodies does not exclude the diagnosis of polymyositis or dermatomyositis.
Clinical Reference
1. Targoff I: Autoantibodies in polymyositis. Rheum Dis Clin North Am 1992;18:455
2. Leff R, Sherman J, Plotz P: Chapter 65: Inflammatory muscle diseases. In Clinical Immunology Principles and Practice, Second edition. Edited by R Rich, T Fleisher, W Shearer, B Kotzin, et al. St. Louis, Mosby-Year Book, 2001, pp 65.1-65.8
Method Description
Recombinant Jo 1 antigen is coupled covalently to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. Jo 1 antibodies, if present in diluted serum, bind to the Jo 1 antigen on the microspheres. The microspheres are washed to remove extraneous serum proteins. Phycoerythrin (PE)-conjugated antihuman IgG antibody is then added to detect IgG anti-Jo 1 bound to the microspheres. The microspheres are washed to remove unbound conjugate, and bound conjugate is detected by laser photometry. A primary laser reveals the fluorescent signature of each microsphere to distinguish it from microspheres that are labeled with other antigens, and a secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing the median fluorescence response for Jo 1 microspheres to a 4-point calibration curve.(Package insert: Bioplex 2200 ANA Screen. Bio-Rad Laboratories, Hercules, CA 03/2012)
Report Available
1 to 3 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
Method Name
Multiplex Flow Immunoassay