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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 ​Thursday​​ only​
(Titer will be performed the following day by IFA)
 ​1-2 days ​Enzyme Immunoassay
Test Information
Test is performed on Thursday. Negative samples will be reported the same day. Positive samples will be tittered​ the following day (​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 ​Thursday​​ 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.