ACTA is an autoantibody that targets actin, a protein involved in cell structure and movement. Anti-actin antibodies can be associated with autoimmune conditions such as autoimmune hepatitis and idiopathic inflammatory myopathies, including dermatomyositis and polymyositis.
| Also Known as | Smooth Muscle Antibody, SMA, Anti-Smooth Muscle Antibody, ASMA, Actin Antibody, F-Actin Antibody, ACTA, Smooth Muscle Antibody Titers, SMAT, Autoantibody |
| Test Purpose | To help diagnose autoimmune hepatitis and distinguish it from other causes of liver injury |
| Test Preparations | No need any Preparation |
| Test Components | Smooth Muscle Antibody Smooth Muscle Antibody Titers |
| Specimen | 2 ML (1 ML Min.) Serum From 1 SST. Ship Refrigerated Or Frozen. Overnight Fasting Is Preferred. |
| Stability Room | 6 Hours |
| Stability Refrigerated | 1 Week |
| Stability Frozen | 2 Weeks |
| Method | Immunofluorescence Assay, ELISA |
| Download Report | Download Report |
SMA titers are determined through laboratory testing, typically using techniques like indirect immunofluorescence (IIF) or enzyme-linked immunosorbent assay (ELISA). These tests compare the patient’s serum to known standards or controls to quantify the level of anti-smooth muscle antibodies present.
If SMA is found in your blood, you probably have autoimmune hepatitis. Autoimmune hepatitis is a disease in which the immune system attacks liver tissues. There are two types of autoimmune hepatitis:
- Type 1, the most common form of the disease. Type 1 affects more women than men. It is also more common in people who also have another autoimmune disorder.
- Type 2, a less common form of the disease. Type 2 mainly affects girls between the ages of 2 and 14.
Autoimmune hepatitis can be controlled with medications that suppress the immune system. Treatment is most effective when the disorder is detected early. Without treatment, autoimmune hepatitis can cause serious health problems, such as cirrhosis and liver failure.
Why Get Tested?
To help diagnose autoimmune hepatitis and distinguish it from other causes of liver injury
When to Get Tested:
You may need this test if you or your child have symptoms of autoimmune hepatitis. These include:
- Fatigue
- Jaundice (a condition that causes the skin and eyes to turn yellow)
- Abdominal pain
- joint pain
- Nausea
- Skin rash
- loss of appetite
- dark colored urine
Preparation for Test:
No Need any Preparation for this test
Sample Required:
Specimen
Serum
Volume
1 mL
Minimum Volume
0.3 mL
Container
Red-top tube or gel-barrier tube
Storage Instructions
Room temperature
Stability Requirements
| Temperature | Period |
|---|---|
| Room temperature | 6 Hours |
| Refrigerated | 1 Week |
| Frozen | 2 Weeks |
| Freeze/thaw cycles | Stable x3 |
Causes for Rejection
Hemolysis; lipemia; gross bacterial contamination; heat-treated specimen; specimen with preservative added
Reference Values
- Negative: 0−19
- Weak positive: 20−30
- Moderate to strong positive: >30
Abnormal Results Reasons
A positive test may be due to:
- Active chronic autoimmune hepatitis
- Cirrhosis
- infectious mononucleosis
The test also helps distinguish autoimmune hepatitis from systemic lupus erythematosus. F-Actin Antibody ACTA
Possible References Used
