Name: ENA Ab
Test Name: ENA Ab
Health Link Test Code: HCENA
LIS Test Code: ENA
CPT Code(s): 86235x4
Qualitative results for SSA (Ro), SSB (La), Sm (Smith)/RNP (Ribonucleic Protein) and Sm (Smith) antibodies.
Methodology: Enzyme Immunoassay
Order only if ANA is positive.
Antibodies to extractable nuclear antigens (SSA, SSB, RNP, Sm) are found in many connective tissue diseases including SLE (SSA, SSB, RNP, Sm), mixed connective tissue disease (high titer RNP), Sjogren's syndrome (SSA, SSB) and scleroderma (SSA, RNP). Sm is very specific for SLE, but not sensitive (30%). Mixed connective tissue disease is almost always (90%) associated with high titer RNP and is associated with antibodies to the 70kd protein by Western blot. SSA is found in approximately 70% of patients with Sjogren's syndrome, whereas SSB is found in 30% of patients. Scleroderma is typically associated with centromere or Scl-70 antibodies, but RNP and SSA are found in a small proportion of patients.
Days Performed: Mon-Fri, dayshift - day varies.
In-Lab Turnaround Time: 1 week.
Stat In-Lab Turnaround Time: Not available stat.
Collection Container: Red top
Also Acceptable: Red cap with yellow ring (SST)
Collection Volume: 3 mL
Pediatric Collection Volume: 1 mL
No limit at -20° C or lower. Note: Avoid repeat freeze and thaw.
Sample Analyzed: Serum
Testing Volume: 1 mL
Pediatric Testing Volume: 0.3 mL
Centrifuge. Transfer cell-free serum to clear plastic vial. Refrigerate.
Transport specimen to Laboratory. Transport with coolant pack if coming from clinic location.
Hemolyzed, grossly lipemic/turbid and icteric specimens are not acceptable.
Normal ENA Ab (0 days and up): Negative or < 20
|SSA, Sm Ab:||Negative|
|SSB, Sm/RNP Ab:||< 20||Negative|
Interpretation Type: Interpretive Guidelines