Autoimmune Liver Disease Evaluation with Reflex to Smooth Muscle Antibody (SMA), IgG by IFA
Ordering Recommendation

Recommended first-line panel for the evaluation of autoimmune liver disease (ALD). Negative results do not rule out disease.

Semi-Quantitative Enzyme-Linked Immunosorbent Assay/Semi-Quantitative Indirect Fluorescent Antibody
Refer to individual components
1-4 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Serum separator tube (SST). 
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transfer 1.0 mL serum to an ARUP Standard Transport Tube. (Min: 0.6 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Non-serum specimens. Contaminated, heat-inactivated, grossly hemolyzed, grossly icteric, severely lipemic 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
0055241Liver-Kidney Microsome - 1 Antibody, IgG0.0-20.0 U:  Negative
20.1-24.9 U:  Equivocal
Greater than or equal to 25.0 U: Positive
0055248F-Actin (Smooth Muscle) Antibody, IgG19 Units or less:  Negative
20-30 Units:  Weak Positive - Suggest repeat testing in two to three weeks with fresh specimen
31 Units or greater:  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 been shown to have greater sensitivity and specificity for autoimmune liver disease than anti-smooth muscle antibodies.

Liver-Kidney Microsome-1 Antibody, IgG by ELISA: A positive result indicates the presence of IgG antibodies to recombinant human P450 2D6 and suggests the possibility of autoimmune hepatitis, type 2. A negative LKM-1 does not rule out the presence of autoimmune hepatitis, type 2.

If F-Actin, IgG result is 20 Units or greater, then Smooth Muscle Antibody, IgG titer will be added. Additional charges apply.
CPT Code(s)
83516 x2; 86376; if reflexed, add 86256
Component Test Code*Component Chart NameLOINC
0050065Mitochondrial (M2) Antibody, IgG14251-3
0055241Liver-Kid Microsome-1 Ab, IgG by ELISA47318-1
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
  • anti-M2
  • Antinuclear Antibodies, Serum
  • F Actin
  • F-actin
  • F-Actin (Smooth Muscle) Antibody, IgG
  • Liver-Kidney Microsome-1 Antibody, IgG
  • LKM1 IgG
  • Mito M2
  • Mitochondrial Antibodies, Serum
  • Mitochondrial M2 Antibody, IgG (ELISA)
  • SMA
  • SMA Titer
  • Smooth Muscle Antibodies, Serum
  • Smooth Muscle Antibody, IgG Titer