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Test Code FACT Filamentous-Actin (F-actin) Antibody, IgG, Serum

Reporting Name

F-Actin Ab, IgG, S

Useful For

Evaluation of patients with hepatitis of unknown origin associated with hypergammaglobulinemia and/or abnormal liver enzymes

 

This test may also be useful for confirming positivity for smooth muscle antibodies.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

Negative: <20.0 U

Weak Positive: 20.0-30.0 U

Positive: >30.0 U

Day(s) Performed

Monday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83516

LOINC Code Information

Test ID Test Order Name Order LOINC Value
FACT F-Actin Ab, IgG, S 44706-0

 

Result ID Test Result Name Result LOINC Value
FACT F-Actin Ab, IgG, S 44706-0

Method Description

The method used to detect antibodies directed against filamentous-actin is enzyme-linked immunosorbent assay. Prediluted controls and diluted patient sera are added to separate wells, allowing any actin antibodies present to bind to the antigen. Unbound sample is washed away, and an enzyme labeled anti-human IgG is added to each well. A second incubation allows the enzyme labeled anti-human IgG to bind to any patient antibodies, which have become attached to the microwells, and any unbound conjugate is removed by another wash step. The bound conjugate is visualized with 3,3',5,5' tetramethylbenzidine (TMB) substrate, which gives a blue reaction product, the intensity of which is proportional to a concentration of autoantibody in the sample. Sulfuric acid is added to each well to stop the reaction. This produces a yellow endpoint color, which is read at 450 nm. Testing is performed on the DS2 instrument by Dynex.(Package insert: QUANTA Lite Actin IgG ELISA 708785. INOVA Diagnostics; Rev. 6, 11/2018)

Report Available

2 to 8 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK
Gross icterus OK
Heat treated specimens Reject

Method Name

Enzyme-Linked Immunosorbent Assay (ELISA)

Secondary ID

61620

Testing Algorithm

For more information see First-Line Screening for Autoimmune Liver Disease Algorithm.