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25303 Smooth Muscle Antibodies, Actin IgG

Smooth Muscle Antibodies, Actin IgG
Test Code: ACTIN
Synonyms/Keywords
Smooth muscle antibody, Actin, F-Actin
Useful For
Useful in the diagnosis of autoimmune hepatitis (AIH).The detection of antinuclear antibodies and/or antismooth muscle antibodies is the hallmark for type 1 AIH. The target antigen of the smooth muscle antibody as it pertains to type 1 AIH is F-actin (filamentous-actin). Definitive diagnosis of AIH should be based on the correlation of all available clinical, biochemical, and liver biopsy information.

Anti-Actin Antibodies are found in 52-85% of patients with AIH or chronic active hepatitis and in 22% of people with primary biliary cirrhosis.

See the Mixed Connective Tissue Disease Panel Algorithm for suggested testing strategy. ​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​1.0 mL ​0.5 mL ​0.5 mL
Collection Processing Instructions

​Separate serum from cells within 2 hours of collection.

Specimen Stability Information

Specimen Type Temperature Time
​Serum ​ ​
​Refrigerate at 2-8 deg Celsius ​2 days
​Freeze at -20 deg Celsius ​> 2 days
Rejection Criteria
Gross Lipemia
Gross Hemolysis
​Heat inactivated samples
​Microbial contaminated samples
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Wednesday only​
(Titer will be performed the following day by IFA)
​1-2 days ​Enzyme Immunoassay
Test Information
Test is performed on Tuesday and Thursday. Negative samples will be reported the same day. Positive samples will be titered the following day (Wednesday or Friday) by IFA. The magnitude of the reported smooth muscle (actin) IgG EIA level cannot be correlated to an endpoint titer.
Reference Range Information
Performing Location Reference Range
​Marshfield ​ ​ < 20.0 Units Negative
​20.0-30.0 Units Weak Positive
​> 30.0 Units Positive
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86015 ​1
Synonyms/Keywords
Smooth muscle antibody, Actin, F-Actin
Ordering Applications
Ordering Application Description

​Cerner
​Smooth Muscle Ab, Actin IgG
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
​No ​Serum ​Red Top Tube (RTT) ​Serum Separator Tube (SST) ​1.0 mL ​0.5 mL ​0.5 mL
Collection Processing

​Separate serum from cells within 2 hours of collection.

Specimen Stability Information

Specimen Type Temperature Time
​Serum ​ ​
​Refrigerate at 2-8 deg Celsius ​2 days
​Freeze at -20 deg Celsius ​> 2 days
Rejection Criteria
Gross Lipemia
Gross Hemolysis
​Heat inactivated samples
​Microbial contaminated samples
Useful For
Useful in the diagnosis of autoimmune hepatitis (AIH).The detection of antinuclear antibodies and/or antismooth muscle antibodies is the hallmark for type 1 AIH. The target antigen of the smooth muscle antibody as it pertains to type 1 AIH is F-actin (filamentous-actin). Definitive diagnosis of AIH should be based on the correlation of all available clinical, biochemical, and liver biopsy information.

Anti-Actin Antibodies are found in 52-85% of patients with AIH or chronic active hepatitis and in 22% of people with primary biliary cirrhosis.

See the Mixed Connective Tissue Disease Panel Algorithm for suggested testing strategy. ​
Reference Range Information
Performing Location Reference Range
​Marshfield ​ ​ < 20.0 Units Negative
​20.0-30.0 Units Weak Positive
​> 30.0 Units Positive
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Marshfield ​Wednesday only​
(Titer will be performed the following day by IFA)
​1-2 days ​Enzyme Immunoassay
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​86015 ​1
For most current information refer to the Marshfield Laboratory online reference manual.