F-Actin and Mitochondrial M2 Antibodies, IgG by ELISA with Reflex to Smooth Muscle Antibody (SMA), IgG by IFA
Ordering Recommendation
Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
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
Unacceptable Conditions
Non-serum, heat-inactivated, contaminated, grossly icteric, severely lipemic, grossly hemolyzed specimens or inclusion of fibrin clot..  
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)  
Reference Interval
Test NumberComponentsReference Interval
0050065Mitochondrial M2 Antibody, IgG (ELISA)20.0 Units or less: Negative
20.1-24.9 Units: Equivocal
25.0 Units or greater: Positive
0055248F-Actin (Smooth Muscle) Antibody, IgG19 Units or less 20-30 Units 31 Units or greater Negative 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.

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
Component Test Code*Component Chart NameLOINC
0050065Mitochondrial (M2) Antibody, IgG14251-3
0055248F-Actin (Smooth Muscle) Ab, IgG by ELISA44706-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
  • AMA M2
  • AMA M2 reflex
  • anti-M2
  • Autoimmune Liver Disease Differentiation Panel
  • F Actin
  • F-actin
  • F-Actin (Smooth Muscle) Antibody, IgG
  • M2
  • Mito M2
  • Mitochondrial Antibodies, Serum
  • Mitochondrial M2 Antibody, IgG (ELISA)
  • Mitochondrial MS reflex
  • SMA
  • SMA Titer
  • Smooth Muscle Antibodies, Serum
  • Smooth Muscle Antibody, IgG Titer