Coxsackievirus B4 Antibody Blood Test (Complement Fixation)
This blood test measures the level of antibodies your body produces against Coxsackievirus B4, a common virus that can cause inflammation of the heart muscle (myocarditis), as well as meningitis, hand-foot-and-mouth disease, and other infections.
{"The test detects antibodies your body produces to fight Coxsackievirus B4","It helps diagnose viral infections that may affect the heart","A first blood sample is taken, often followed by a second sample 2-4 weeks later","Results show whether you have a current or past infection","The test uses complement fixation method to detect antibody levels"}
Key facts at a glance
- LOINC
- 24189-3
- Short code
- COXB4
- Synonyms
- CV B4 Ab sp1 Titr Ser CF
- Category
- cardiac
- Sample
- serum
- Container
- Serum separator tube (SST) or red top tube
- Units
- N/A
- Ref low
- 8
- Ref high
- 8
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 0–120 years
- Method
- comp-fix
- CPT
- 86658
- SNOMED
- 122444004
- Specimen volume
- 1-2 mL of serum
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 48-72 hours; Frozen (-20°C or below): several weeks. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 100
- Icterus max
- 20
- TAT
- 48–168 hours
- Order
- routine
What is this test?
The Coxsackievirus B4 antibody test is a blood test that looks for antibodies your immune system makes in response to Coxsackievirus B4, a type of enterovirus. This virus can cause various infections, including myocarditis (heart muscle inflammation), meningitis, and hand-foot-and-mouth disease. The test uses a method called complement fixation to detect and measure these antibodies in your blood.
Why is it ordered?
This test is most commonly ordered when you have symptoms of myocarditis or another infection caused by Coxsackievirus B. Symptoms may include chest pain, shortness of breath, fatigue, fever, muscle aches, or flu-like symptoms. Your doctor may also order this test if you have unexplained heart problems or if you work in healthcare and may have been exposed to the virus.
How is the test performed?
A healthcare professional will draw a blood sample from a vein in your arm. This is typically your first specimen. In many cases, a second blood sample is drawn 2-4 weeks later to compare antibody levels and determine if the infection is recent or past. The blood sample is sent to a laboratory where it is tested using the complement fixation method.
What do the results mean?
Results are usually reported as a titer (a measure of how much antibody is present). A fourfold increase in antibody levels between your first and second blood samples indicates a recent or active infection. A single high titer may indicate a current infection, while lower or stable titers may suggest a past infection. Your doctor will interpret these results along with your symptoms and other test findings.
Reference range
Negative: <1:8; Borderline: 1:8; Positive: >1:8. A fourfold rise in titer between acute and convalescent specimens indicates recent infection.N/A
No special preparation required. Fasting is not necessary. Inform the laboratory of any recent infections or immunizations.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Coxsackievirus B4 is one of the most common causes of viral myocarditis, an inflammation of the heart muscle that can lead to chest pain, heart failure, and in severe cases, sudden cardiac death. This test helps confirm whether a Coxsackievirus infection is responsible for heart symptoms. It is also useful for diagnosing aseptic meningitis and other complications caused by this virus. Early detection can help guide treatment and monitor for potential heart complications.
Frequently asked questions
Do I need to fast before this test?
Is the test painful?
How long does it take to get results?
What happens if my test is positive?
Do I need a second blood test?
Sources
- 1
- 2CDC - Enterovirus D68Source
- 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 10, 2026. · Read our editorial policy