Useful in the differential diagnosis of connective tissue diseases with or without myopathy.
Semi-Quantitative Enzyme-Linked Immunosorbent Assay
New York DOH Approval Status
Serum separator tube.
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)
Plasma or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 30 days (avoid repeated freeze/thaw cycles)
|19 Units or less||Negative|
|20-39 Units||Weak Positive|
|40-80 Units||Moderate Positive|
|81 Units or greater||Strong Positive|
Smith/RNP antibodies are frequently seen in patients with mixed connective tissue disease (MCTD) and are also associated with other systemic autoimmune rheumatic diseases (SARDs), such as systemic lupus erythematosus (SLE), systemic sclerosis, and myositis. Antibodies targeting the Smith/RNP antigenic complex also recognize Smith antigens, therefore, the Smith antibody response must be considered when interpreting these results.
An affinity purified RNP/Sm antigen complex is used in this assay.
|Component Test Code*||Component Chart Name||LOINC|
|0050470||Smith/RNP (ENA) Ab, IgG||33983-8|