Autoimmune Liver Disease Evaluation with Reflex to Smooth Muscle Antibody (SMA), IgG by IFA
Ordering Recommendation
Submit With Order
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.
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 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
0055241 Liver-​Kidney Microsome -​ 1 Antibody, IgG 0.0-​20.0 U: Negative
20.1-​24.9 U: Equivocal
Greater than or equal to 25.0 U: Positive
0055248 F-​Actin (Smooth Muscle) Antibody, IgG 19 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 Name
0050065Mitochondrial (M2) Antibody, IgG
0055241Liver-Kid Microsome-1 Ab, IgG by ELISA
0055248F-Actin (Smooth Muscle) Ab, IgG by ELISA
* 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.
Cross References
  • 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