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May 15, 2017

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100

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Clinical Hub,Tools & Resources,UWHC Lab Test Directory,Immunology

ENA Ab

ENA Ab (HCENA) Immunology Lab Test

Name: ENA Ab

Test Name: ENA Ab

Health Link Test Code: HCENA

LIS Test Code: ENA

CPT Code(s): 86235x4

Test Component:

Qualitative results for SSA (Ro), SSB (La), Sm (Smith)/RNP (Ribonucleic Protein) and Sm (Smith) antibodies.

Methodology: Enzyme Immunoassay

Clinical Information:

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.

Specimen: Blood

Collection Container: Red top

Also Acceptable: Red cap with yellow ring (SST)

Collection Volume: 3 mL

Pediatric Collection Volume: 1 mL

Stability Ambient:

8 hours

Stability Refridgerated:

7 days

Stability Frozen:

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

Specimen Processing:

Centrifuge. Transfer cell-free serum to clear plastic vial. Refrigerate.

Specimen Transport:

Transport specimen to Laboratory. Transport with coolant pack if coming from clinic location.

Unacceptable Criteria:

Hemolyzed, grossly lipemic/turbid and icteric specimens are not acceptable.

Interpretation:

Normal ENA Ab (0 days and up): Negative or < 20

 

 SSA, Sm Ab:    Negative
 SSB, Sm/RNP Ab:     < 20  Negative
 20-39  Borderline
 40-80  Moderate Positive
 >80  Strong Positive

 

          

      

 

       

Interpretation Type: Interpretive Guidelines