F-Actin Antibody Test Purpose, Procedure, Result Interpretation and Your Test Result Meaning

The F-Actin antibody refers to an antibody that specifically targets filamentous actin (F-actin). Actin is a protein found in all eukaryotic cells and plays a crucial role in cell structure, movement, and various cellular processes.

This test looks for Smooth muscle antibodies (SMA) in the blood. A smooth muscle antibody (SMA) is a type of antibody known as an autoantibody. Normally, your immune system makes antibodies to attack foreign substances like viruses and bacteria. An autoantibody attacks the body’s own cells and tissues by mistake. SMAs attack smooth muscle tissues in the liver and other parts of the body.

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

---