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Serum/plasma mass concentration of immunoglobulin M (IgM) antibodies against Epstein-Barr virus (EBV) capsid antigen (VCA)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of IgM antibodies in your blood that target the Epstein-Barr virus (EBV) capsid antigen. IgM is one of the first types of antibodies your immune system produces in response to infection.

Quick summary

["Helps determine if you recently had an EBV infection or are recovering from it."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
85498-4
Short code
blaIMP
Synonyms
blaIMP Islt/Spm Ql
Category
chemistry
Sample
serum
Container
Sterile, leak-proof container or appropriate transport medium (e.g., Eswab transport system, sterile screw-cap tube); EDTA tube acceptable for blood specimens
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 0 years
Method
molgen
CPT
87150
SNOMED
104426006
Specimen volume
1-2 mL of serum or fluid; 1-5 mL of whole blood; or appropriate volume per specimen type
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-70°C or below): longer storage acceptable for nucleic acid preservation
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

What Does This Test Measure?

IgM antibodies are part of your immune system’s immediate response to infections. When you’re exposed to EBV, your body produces these antibodies quickly to fight the virus. This test specifically looks for IgM antibodies that target the EBV capsid antigen, which is a common protein found in the virus.

Why Might You Need This Test?

Your healthcare provider may order this test if you have symptoms like fever, fatigue, sore throat, or swollen lymph nodes, which can be signs of EBV infection. It’s also used to monitor how your body is responding to treatment if you’ve already been diagnosed with EBV-related conditions.

What Are Common Symptoms?

EBV infection can cause a range of symptoms, including persistent sore throat, swollen glands, fever, fatigue, and sometimes more severe complications like hair loss or neurological issues. If these symptoms persist or worsen, your doctor might recommend this test to check for EBV infection.

How Is This Test Performed?

A blood sample is taken from a vein in your arm. The sample is then sent to a lab for analysis. The lab uses a specialized immunoassay method to detect the presence of IgM antibodies against EBV capsid antigen in your serum or plasma.

Reference range

Negative for blaIMP gene (Not Detected). A positive result indicates the presence of the blaIMP carbapenem resistance gene.N/A

Specimen: serum

No special patient preparation or fasting required. Specimen should be collected prior to initiation of antibiotic therapy when possible. For surveillance cultures, follow institutional infection control protocols.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgM EBV VCA Antibody (Serum/Plasma)

Frequently asked questions

IgM EBV VCA antibodies are typically present in the blood during the early stages of an EBV infection. They decline as your immune system produces other types of antibodies (like IgG) over time. High levels of IgM can indicate an acute infection, while lower levels may suggest recovery or past infection. This test is useful for diagnosing recent EBV exposure, especially in cases where symptoms are mild or unclear.
How soon after infection might I start seeing positive results?
IgM antibodies usually appear within 2 to 4 weeks after EBV exposure and can remain detectable for several months. However, results can vary depending on the individual’s immune response and the stage of infection.
Can this test be used to diagnose long-term EBV-related conditions?
While this test helps identify recent EBV infection, it’s not typically used to diagnose chronic conditions like infectious mononucleosis or EBV-related lymphomas. Other tests, including IgG EBV VCA antibodies and viral load testing, may be needed for those purposes.
If your IgM EBV VCA test is positive, your healthcare provider may recommend further testing or monitoring. They could also suggest managing symptoms with rest, hydration, and over-the-counter pain relievers. Follow-up visits may be scheduled to track your recovery or address any ongoing concerns.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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