Antinuclear Antibodies (ANA), IgG by ELISA with Reflex to ANA HEp-2 Substrate, IgG by IFA and ENA Confirmation
Also known as: ANA REF
Use
This test aids in the initial diagnosis of connective tissue diseases, such as systemic autoimmune rheumatic diseases (SARDs). It may be used to screen for antibodies against dsDNA, histones, SS-A, SS-B, Smith, Smith/RNP, Scl-70, Jo-1, centromeric proteins, and other nuclear antigens. It helps determine the presence of antinuclear antibodies, which are characteristic of various autoimmune disorders, including systemic lupus erythematosus (SLE) and Sjögren syndrome.
Special Instructions
Positive ANA detected by ELISA prompts further testing through reflex to indirect fluorescent assay (IFA) based on HEp-2 cell substrate. If ANA IgG is detected by IFA, further reflex testing for specific extractable nuclear antigen (ENA) antibodies is performed, with additional charges applying. The results may guide more specific serologic testing for confirmation.
Limitations
ANA testing lacks diagnostic specificity as ANAs are present in a variety of diseases, including cancers, autoimmune, infectious, and inflammatory conditions, and can also occur in healthy individuals. ELISA screening may have lower sensitivity compared to IFA, and negative results do not rule out systemic autoimmune rheumatic diseases. Reflex testing with IFA and further ENA antibody testing are needed for comprehensive evaluation.
New York Approved
Methodology
Immunoassay (ELISA)
Biomarkers
LOINC Codes
- 29950-3
Result Turnaround Time
1-5 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1.0 mL
Minimum Volume
1.0 mL
Container
ARUP standard transport tube
Collection Instructions
Separate serum from cells ASAP or within 2 hours of collection.
Storage Instructions
Refrigerated.
Causes for Rejection
Nonserum specimens. Contaminated, grossly hemolyzed, heat-inactivated, severely lipemic specimens, or inclusion of fibrin clots.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 48 hours |
| Refrigerated | 2 weeks |
| Frozen | 1 month (avoid repeated freeze/thaw cycles) |