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HelpTest Code ENAE; SQ: EXNAG Antibody to Extractable Nuclear Antigen Evaluation, Serum
Reporting Name
Ab to Extractable Nuclear Ag Eval,SUseful For
Evaluating patients with clinical features suggestive of antinuclear antibody (ANA) associated connective tissue disease. May also be indicated in patients who test negative for ANA and have features of Sjogren syndrome and idiopathic inflammatory myopathies
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| SSA | SS-A/Ro Ab, IgG, S | Yes | Yes |
| SSB | SS-B/La Ab, IgG, S | Yes | Yes |
| SM | Sm Ab, IgG, S | Yes | Yes |
| RNP | RNP Ab, IgG, S | Yes | Yes |
| SCL70 | Scl 70 Ab, IgG, S | Yes | Yes |
| JO1 | Jo 1 Ab, IgG, S | Yes | Yes |
Testing Algorithm
For more information see Connective Tissue Disease Cascade.
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
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
SS-A/Ro ANTIBODIES, IgG
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
SS-B/La ANTIBODIES, IgG
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Sm ANTIBODIES, IgG
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
RNP ANTIBODIES, IgG
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Scl 70 ANTIBODIES, IgG
<1.0 U (negative)
≥1.0 U (positive)
Reference values apply to all ages.
Jo 1 ANTIBODIES, IgG
<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 x 6
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ENAE | Ab to Extractable Nuclear Ag Eval,S | 90228-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| JO1 | Jo 1 Ab, IgG, S | 33571-1 |
| RNP | RNP Ab, IgG, S | 29958-6 |
| SCL70 | Scl 70 Ab, IgG, S | 47322-3 |
| SM | Sm Ab, IgG, S | 18323-6 |
| SSA | SS-A/Ro Ab, IgG, S | 33610-7 |
| SSB | SS-B/La Ab, IgG, S | 33613-1 |
Clinical Information
Antibodies to SS-A/Ro, SS-B/La, Smith (Sm), U1RNP (RNP68/A), Scl 70 and JO1 are associated with the presence of antinuclear antibodies (ANA) and useful in the evaluation of specific ANA-associated connective tissue diseases (CTD), ANA-CTD.(1) Due to their frequencies in ANA-CTD and the overlapping clinical presentations of these diseases, inclusion of these tests in a panel may be useful at initial evaluation of patients at-risk for certain CTD. The combined presence of antibodies to SS-A/Ro (Ro52 and Ro60) and anti-SS-B/La is highly suggestive of Sjogren syndrome.(2,3) Separate determination of anti-Ro52 and anti-Ro60 antibodies is preferred to combined SS-A/Ro in the evaluation of ANA-CTD as their differential presence maybe useful in risk stratification and prognosis of ANA-CTD patients.(4) The presence of anti-Sm antibodies are specific for systemic lupus erythematosus (SLE) and is included the classification criteria for disease.(5) Monospecific antibody reactivity to U1RNP may indicate a diagnosis of mixed connective tissue disease (MCTD).(6) However, anti-U1RNP antibodies may also be seen in patients with SLE, systemic sclerosis (SSc) and idiopathic inflammatory myopathies (IIM).(6,7) In addition, there exists diverse analytes for the detection U1RNP with differential correlations with MCTD, SLE, SSc, and IIM.(8) Anti-Scl 70 (topoisomerase 1) antibody is one of three autoantibodies included in the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc.(9). It is generally associated with diffuse cutaneous SSc clinical manifestations including interstitial lung disease with poor prognostic outcomes.(10) Lastly, antibodies to JO1, is a member of the amino acyl-tRNA synthetase family of enzymes is suggestive of diagnosis of IIM, specifically anti-synthetase syndrome and is included in the 2017 EULAR/ACR classification for IIM.(11)
For more information, see the individual test codes.
Interpretation
A positive antibody result in the appropriate clinical context maybe suggestive of connective tissue disease.
For more information, see the individual test codes.
Method Description
Antigen is coupled covalently to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. Antibodies, if present in diluted serum, bind to the 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 antibodies 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 microspheres to a 4-point calibration curve.(Package insert: Bioplex 2200 ANA Screen. Bio-Rad Laboratories; 02/2019)
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | OK |
| Heat-Treated | Reject |
Method Name
Multiplex Flow Immunoassay