Complete Blood Count (CBC)
The Actin Antibody test detects specific autoantibodies in your blood that help diagnose autoimmune hepatitis, a condition where the immune system attacks the liver.
{"Actin antibodies are markers for type I autoimmune hepatitis","This test uses immunofluorescence to detect antibodies in blood","Positive results suggest your immune system may be attacking your liver","Results are interpreted alongside other liver tests and clinical symptoms","Follow-up with a specialist is important for proper diagnosis"}
Key facts at a glance
- LOINC
- 53979-1
- Short code
- ACTAB
- Synonyms
- Actin Ab SerPl Ql IF
- Category
- chemistry
- Sample
- serum
- Container
- Serum separator tube (SST) or plain red top tube
- Units
- N/A
- Ref low
- 0
- Ref high
- 1
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Immunofluorescence (IFA)
- CPT
- 86635
- SNOMED
- 413215006
- Specimen volume
- 1.0 mL minimum (2.0 mL preferred)
- Stability
- Room temperature: 48 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 300
- Icterus max
- 40
- TAT
- 72–168 hours
- Order
- routine
What is a complete blood count (CBC) and what does it measure in my blood?
The Actin Antibody test is a blood test that detects the presence of actin antibodies (also called anti-smooth muscle antibodies or ASMA) in your serum or plasma. Actin is a protein found in muscle cells, and when your immune system produces antibodies against it, this can indicate an autoimmune condition affecting your liver.
How is a complete blood count performed, and how should I prepare for the blood draw?
A healthcare provider will collect a blood sample from a vein in your arm. The sample is then sent to a laboratory where it is analyzed using an immunofluorescence technique. This method uses fluorescent dyes to detect and measure the level of actin antibodies in your blood. The result is reported as either positive or negative (presence or absence).
Why might my doctor order a complete blood count during a routine checkup or when I feel ill?
Your doctor may order this test if you have symptoms of liver disease such as jaundice, fatigue, abdominal pain, or unexplained elevated liver enzymes. It is primarily used to help diagnose autoimmune hepatitis, particularly type I autoimmune hepatitis, which is more common in women and often occurs in younger to middle-aged adults.
What do the results of a complete blood count mean for my overall health?
A positive result means actin antibodies were detected in your blood. This finding, especially at high titers, suggests you may have type I autoimmune hepatitis. However, actin antibodies can also be found in some other autoimmune conditions and occasionally in healthy individuals. Your doctor will interpret your results together with other liver function tests, clinical symptoms, and possibly additional antibody tests to make an accurate diagnosis.
Are there any risks or side effects from having my blood drawn for this test?
The risks associated with this blood test are minimal and include slight pain or bruising at the needle site, fainting, or infection. These risks are generally minor and temporary.
Reference range
Negative: < 1:20 titer; Positive: ≥ 1:20 titerN/A
No special preparation required. Fasting is not necessary for this test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The Actin Antibody test is primarily used to diagnose type I autoimmune hepatitis (AIH), a condition in which the immune system mistakenly attacks liver cells. High titers of actin antibodies are strongly associated with AIH type I and can help differentiate it from other liver diseases like viral hepatitis or primary biliary cholangitis. The presence of actin antibodies, particularly at high levels (≥1:160), is a key diagnostic criterion for AIH. This test is often ordered alongside other autoantibody tests such as ANA (antinuclear antibody) and LKM-1 (liver-kidney microsomal antibody) to provide a complete picture of potential autoimmune liver disease.
Frequently asked questions
Do I need to fast before this test?
Can actin antibodies be found in healthy people?
What happens if my test is positive?
Is autoimmune hepatitis treatable?
How long does it take to get results?
Sources
- 1
- 2
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 14, 2026. · Read our editorial policy