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Test ID: ENA Jo-1
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ENA Jo-1
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Anti- histidyl tRNA synthetase antibodies
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Useful For
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When a patient shows signs and symptoms of a connective tissue disease and the test for antinuclear antibodies (CTD) is positive, evaluating the patient with Extractable Nuclear Antigens Jo-1 (ENA Jo-1) can aid in the clinical diagnosis of polymyositis/dermatomyositis. However, it's important to note that a negative test for Jo-1 antibodies does not necessarily exclude the diagnosis of polymyositis or dermatomyositis..
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Method name and description
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Method: Fluorescence Enzyme Immunoassay (FEIA), Uses the EliA IgG method on Phadia system.
Using EliA technology solid phase, analyte molecules can be extracted from a sample. To achieve this, a well is coated with an antigen that specifically binds to target antibodies. Following the removal of non-bound antibodies, enzyme-labeled antibodies against human antibodies (EliA IgG Conjugate) are added to form an antibody conjugate complex. This complex is then incubated and non-bound conjugate is subsequently washed away. The bound complex is then incubated with a Development Solution, and after stopping the reaction, the fluorescence in the reaction mixture is measured. A higher response value indicates the presence of a more specific antibody in the specimen.
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Clinical information
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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 can be found as markers in dermatomyositis/ polymyositis (prevalence of about 25 %), but also in patients with polymyositis overlap syndrome. They are associated with interstitial pneumonitis (in the context of myositis) and occur in a far smaller proportion of children with myositis than of adults. Patients with Jo-1 antibodies tend to have a severe form of the disease with a tendency to relapse and a poorer prognosis.Poly-/dermatomyositis (PM/DM) is an acute or chronic inflammatory disease of muscle and skin that may occur at any age. Women are affected twice as commonly as men.
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Aliases
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ENA Jo-1
Anti Jo-1
Anti-histidyl Transfer RNA Synthase Antibodies
Anti-ENA (Antibodies to Extractable Nuclear Antigens)
Autoantibodies to Jo 1 Antigen
Polymyositis Antibodies
Dermatomyositis Antibodies
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Specimen type / Specimen volume / Specimen container
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Specimen type: Serum sample.
Specimen Volume: At minimum 2 mL whole blood or 0.5 mL serum.
Container Tube: Plan tube /Serum gel (Yellow top tubes).
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Storage and transport instructions
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For sample transportation, the sample should remain at room temperature (18-25°C ) for no longer than eight hours.
Separated serum samples can be stored at 2-8°C for one week.
Separated serum samples should be frozen at below -20°C for any long-term storage.
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Specimen Rejection Criteria
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Quantity not sufficient (QNS)
Hemolysis
Lipemic
Wrong collection container
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Biological reference intervals and clinical decision values
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Anti-ENA Jo-1 antibodies:
| Interpretation of Test Results |
Reference Values (U/ml) |
| Negative |
< 7 |
| Equivocal |
7 - 10 |
| Positive |
> 10 |
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Turnaround time / Days and times test performed / Specimen retention time
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Turnaround Time: 5 working days.
Days and Times test performed: Twice per week starting from Sunday through Thursday from 7:00 to 15:00.
Specimen retention time: Approximately 7 days.
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