Mar 23, 2015




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

Smith Ab

Smith Ab (HCSMITH) Immunology Lab Test

Name: Smith Ab

Test Name: Smith Ab

Health Link Test Code: HCSMITH

LIS Test Code: SMITH

CPT Code(s): 86235

Included In: ENA Ab

Methodology: Enzyme Immunoassay

Clinical Information:

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.

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 UWHC Hospital Laboratory. Transport with coolant pack if coming from clinic location.

Unacceptable Criteria:

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


Normal Smith Ab (0 days and up):  Negative