: EBV Viral Capsid Antigen IgM Antibody, Serum or Plasma by Immunoassay
: This test looks for IgM antibodies against the Epstein-Barr virus viral capsid antigen in a blood sample. It is used to help determine whether a person has a recent or active Epstein-Barr virus infection.
[": A positive EBV VCA IgM result generally suggests a recent Epstein-Barr virus infection, but results must be interpreted together with other EBV tests and clinical findings."]
Key facts at a glance
- LOINC
- 48673-8
- Short code
- EBV-LMP Ag Tiss Ql ImStn
- Synonyms
- EBV-LMP Ag Tiss Ql ImStn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- immune-stain
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
: What Is Being Tested
: The test measures immunoglobulin M (IgM) antibodies that the immune system produces against the viral capsid antigen (VCA) of Epstein-Barr virus. IgM antibodies typically appear early after infection and decline over time.
: Why the Test Is Ordered
: Healthcare providers may order this test when someone has symptoms suggesting infectious mononucleosis or another EBV-related illness, such as fever, sore throat, swollen lymph nodes, and fatigue. It is often ordered together with other EBV antibody tests to clarify the stage of infection.
: How the Sample Is Collected
: A blood sample is collected from a vein, usually in the arm, and the serum or plasma is separated for testing. No special preparation is generally required.
: How Results Are Interpreted
: Results are reported as positive, negative, or sometimes equivocal. A positive IgM result may indicate a recent infection, while a negative result makes a recent infection less likely. Because IgM can sometimes persist or be nonspecific, results are best interpreted alongside VCA IgG, EBV nuclear antigen (EBNA) antibodies, and the patient's symptoms.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
: EBV VCA IgM testing helps distinguish recent from past Epstein-Barr virus infection. It is most useful when combined with other EBV serologic markers and clinical information, since no single antibody result is definitive in all cases.
Short name
: EBV VCA IgM
Frequently asked questions
: Does a positive EBV VCA IgM mean I currently have mono?
: Can EBV VCA IgM stay positive for a long time?
: Do I need to fast before this test?
Sources
- 1
- 2Lab Tests OnlineSource
- 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 16, 2026. · Read our editorial policy