Coxsackievirus A2 Antibody Test (Complement Fixation)
This blood test measures antibodies against Coxsackievirus A2 in your blood using a laboratory method called complement fixation. It helps your healthcare provider find out whether your immune system has responded to a recent or past Coxsackievirus A2 infection, which can cause symptoms like fever, sore throat, rash, or heart-related complications such as myocarditis, and supports an accurate diagnosis of related infections.
{"Detects antibodies to Coxsackievirus A2, an enterovirus that can cause hand-foot-and-mouth disease and other infections","Uses complement fixation test to measure antibody levels (titers) in blood serum","Helps diagnose recent or past Coxsackievirus A2 infections, particularly when cardiac or neurological symptoms are present","Sample is collected through a simple blood draw","Results are reported as antibody titers, with higher levels indicating stronger immune response"}
Key facts at a glance
- LOINC
- 9753-5
- Short code
- COXA2CF
- Synonyms
- CV A2 Ab Titr Ser CF
- Category
- cardiac
- Sample
- serum
- Container
- SST (Serum Separator Tube) or red top glass 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
- 122449000
- Specimen volume
- 1.0 mL minimum, 2.0 mL preferred
- Stability
- Room temperature: 8 hours; Refrigerated (2-8°C): 48 hours; Frozen (-20°C or below): 7 days. Avoid repeated freeze-thaw cycles.
- Hemolysis max
- 50
- Lipemia max
- 40
- Icterus max
- 20
- TAT
- 72–168 hours
- Order
- routine
What is this test?
The Coxsackievirus A2 antibody test is a blood test that detects and measures specific antibodies (called IgG and IgM) against Coxsackievirus A2 in your blood serum. The test uses a laboratory method called complement fixation, which can determine whether your immune system has produced antibodies in response to a Coxsackievirus A2 infection. This test is often ordered when patients show symptoms that may be related to Coxsackievirus infection, especially when cardiac complications are suspected.
Why is it ordered?
Healthcare providers may order this test to: (1) Confirm a suspected Coxsackievirus A2 infection in patients with symptoms such as fever, sore throat, rash (particularly on hands, feet, and mouth), or vesicles in the mouth; (2) Investigate the cause of myocarditis (heart muscle inflammation) or pericarditis (heart lining inflammation) when Coxsackievirus is suspected as the underlying cause; (3) Determine if a patient has been previously exposed to Coxsackievirus A2; (4) Monitor antibody levels in certain clinical situations.
How is the test performed?
A healthcare professional will draw a small blood sample from a vein in your arm. The blood is collected in a tube and sent to a laboratory for analysis. In the laboratory, technicians use the complement fixation test method, which detects whether specific antibodies in your blood can bind to Coxsackievirus A2 antigens and trigger the complement system. The results are reported as a titer, which indicates the highest dilution of your blood serum that still shows a positive reaction.
What do the results mean?
Results are typically reported as a titer (for example, 1:8, 1:32, 1:64). A fourfold increase in antibody titer between two blood samples taken 2-4 weeks apart indicates a recent or ongoing infection. A single elevated titer may indicate past exposure to the virus. Your healthcare provider will interpret the results in the context of your symptoms, physical examination, and other test results to make an accurate diagnosis.
Reference range
Less than 1:8 (negative); 1:8 (borderline); Greater than 1:8 (positive). A four-fold rise in titer between acute and convalescent samples indicates recent or ongoing infection.N/A
No special preparation required. Fasting is not necessary for this test.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Coxsackievirus A2 is a member of the Enterovirus genus and is a common cause of hand-foot-and-mouth disease (HFMD) in children, characterized by fever, sore throat, and painful blisters on the hands, feet, and inside the mouth. While most infections are mild and self-limiting, Coxsackieviruses can occasionally cause more serious complications, including myocarditis (inflammation of the heart muscle), pericarditis (inflammation of the heart lining), aseptic meningitis, and encephalitis. This test helps clinicians identify whether a patient has been infected with Coxsackievirus A2, which is particularly important when cardiac symptoms are present, as it can guide treatment decisions and help determine prognosis.
The complement fixation test is a classic serological method that detects virus-specific antibodies by measuring their ability to fix (consume) complement proteins. A positive result indicates that the patient's immune system has produced specific antibodies against Coxsackievirus A2. The presence of IgM antibodies typically indicates a recent infection, while IgG antibodies suggest past exposure or immunity. This test is particularly useful in epidemiological studies and outbreak investigations to determine the prevalence of Coxsackievirus A2 infections in communities.
Frequently asked questions
Do I need to fast before this test?
Is this test painful?
How long does it take to get results?
What is the difference between IgM and IgG antibodies?
Do I need treatment if the test is positive?
Can I get Coxsackievirus A2 more than once?
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 10, 2026. · Read our editorial policy