| Label Mnemonic: | ACTIN |
| Epic code: | LAB8686 |
| Order form: | Laboratory Requisition |
| Supply order: | Supply Order Form |
| Billing: | Billing Policies |
| CPT code: | 83516 |
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| Red top tube 5 mL (Clot Activator) |
Preferred Minimum: 0.5 mL serum
Absolute Minimum: 0.4 mL serum
Plasma. Contaminated, heat-inactivated, hemolyzed, or lipemic specimens.
2 – 8 days upon receipt at reference laboratory
Negative: <20.0 U
Weak Positive: 20.0-30.0 U
Positive: >30.0 U
Positivity for anti-filamentous-actin (F-actin) antibodies may help support a diagnosis of autoimmune hepatitis (AIH) following exclusion of other causes of hepatitis.
A negative result for anti-F-actin antibodies does not exclude a diagnosis of AIH.
In a study conducted at Mayo Clinic, the F-actin enzyme-linked immunosorbent assay (ELISA) had a clinical sensitivity of 92.9% when using the manufacturer's recommended cutoff of 20.0 U. In addition, the F-actin ELISA had a clinical specificity of 76.7% when using the aforementioned cutoffs. See Supportive Data.
In viral hepatitis the titers are generally less than 1:80 and are transient. The titers in primary biliary cirrhosis are also low, ranging from 1:20 to 1:40.
If F-Actin is 20 Units or greater, then Smooth Muscle Ab, IgG IFA titer will be added. Additional charges apply.
Enzyme-Linked Immunosorbent Assay (ELISA)
Centrifuge within two hours of draw time.
Label transport tube with patient last name, first name, identification number, date and time of collection.
Transfer serum into new screw-capped plastic vial.
Hemolyzed samples are not acceptable.
Place completed requisition into outside pocket of bag.
Place dry ice on top of specimen in Styrofoam container to maintain frozen temperature.