ARUP's Laboratory Test Directory

F-Actin and Mitochondrial M2 Antibodies, IgG by ELISA with Reflex to Smooth Muscle Antibody (SMA), IgG by IFA : 2007209
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Additional Technical Information
  


Mnemonic: ACTIN/M2 R

Methodology: Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody
Performed: Sun-Sat
Reported: 1-4 days
Specimen Required: Collect: Serum separator tube (SST).

Specimen Preparation: Separate serum from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)

Storage/Transport Temperature: Refrigerated.

Unacceptable Conditions: Non-serum, heat-inactivated, contaminated, grossly icteric, severely lipemic, grossly hemolyzed specimens or inclusion of fibrin clot..

Stability (collection to initiation of testing): After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
Reference Interval:
 
Test Number Components Reference Interval
0050065 Mitochondrial M2 Antibody, IgG (ELISA) 20.0 Units or less: Negative
20.1-24.9 Units: Equivocal
25.0 Units or greater: Positive
0055248 F-Actin (Smooth Muscle) Antibody, IgG 19 Units or less 20-30 Units 31 Units or greaterNegative  Weak Positive - Suggest repeat testing in two to three weeks with fresh specimen. Positive - Suggestive of autoimmune hepatitis type 1 or chronic active hepatitis.
 Smooth Muscle Antibody, IgG Titer <1:20 = Normal - No antibody detected.
1:20-1:80 = Weak Positive - Suggest repeat testing in two to three weeks with fresh specimen.
1:160 or greater = Positive - Suggestive of autoimmune hepatitis or chronic active hepatitis.

Interpretive Data: F-Actin Antibody, IgG by ELISA: F-actin antibodies have demonstrated a greater sensitivity and specificity for autoimmune liver disease than anti-smooth muscle antibodies.
Note: If F-Actin, IgG by ELISA is 20 Units or greater, then Smooth Muscle Antibody (SMA), IgG by IFA titer will be added. Additional charges apply.
CPT Code(s): 83516 x2; if reflexed, add 86256
Cross References: Autoimmune Hepatitis (AIH), Autoimmune Liver Disease Differentiation Panel , Primary Biliary Cirrhosis (PBC)