EBV CAPSID Ag.ab/IgG
Other names: EBV VIRAL CAPSID AG (VCA) AB (IGG), Epstein-Barr Virus, Antibody To Viral Capsid Antigen, IgG
Epstein–Barr Virus (EBV) — Antibody to Viral Capsid Antigen (VCA), IgG
What this test measures
This test detects IgG antibodies your immune system makes against the viral capsid antigen of Epstein–Barr virus (EBV). Once you’ve been infected, VCA-IgG usually becomes positive for life, showing you’ve been exposed at some point. By itself, VCA-IgG does not prove current infection; it must be interpreted with other EBV markers (VCA-IgM, EBNA-IgG, ± Early Antigen [EA] IgG) and your symptoms.
Other names: EBV Capsid Ag Ab/IgG
Why it matters
-
EBV is very common and often causes only mild illness.
-
It spreads easily through saliva (kissing, sharing drinks, utensils).
-
First infection in adolescence or early adulthood can cause “mono” (infectious mononucleosis) with tiredness, fever, sore throat, and swollen lymph nodes.
-
After recovery, EBV stays dormant in your body and may reactivate occasionally, usually without major problems unless your immune system is weakened.
Reference range (U/mL)
-
< 18.0: Negative
-
18.0 – 21.9: Equivocal
-
≥ 22.0: Positive
Note: Units and cutoffs vary by lab. Always check the range on your report.
How to interpret your result
Negative (< 18.0 U/mL): Suggests no prior EBV infection or very early infection before antibodies form.
-
If you have mono-like symptoms but VCA-IgG is negative, your clinician may add VCA-IgM, EBNA-IgG, EA-IgG, or EBV DNA (PCR), or repeat the test in 1–2 weeks.
-
Other illnesses can mimic mono (e.g., CMV, hepatitis viruses, rubella, toxoplasmosis, strep throat).
Equivocal (18.0–21.9 U/mL): Borderline result, sometimes due to very early infection, test variation, or low antibody levels.
-
Repeat the test in 1–2 weeks.
-
Adding companion markers (VCA-IgM, EBNA-IgG, ± EA-IgG) gives clearer answers.
Positive (≥ 22.0 U/mL): Shows you were infected with EBV at some point in the past.
-
Most healthy adults test positive—this is normal and does not mean active illness.
-
To check for recent vs. remote infection, doctors compare patterns of different EBV antibodies:
Typical EBV serology patterns
| Clinical stage | VCA-IgM | VCA-IgG | EBNA-IgG | What it means |
|---|---|---|---|---|
| Early/acute infection | + | + | − | Consistent with recent infection |
| Past infection | − | + | + | Previous exposure; not active illness |
| Very early “window” | − | − | − | No antibodies yet; retest if suspicion remains |
| Possible reactivation* | ± | + | + | Depends on symptoms; may need EA-IgG or PCR |
* Reactivation patterns vary—always interpreted with symptoms and context.
Who might need this test
-
People with mono-like symptoms (fatigue, fever, sore throat, swollen glands).
-
Patients with a negative or inconclusive “mono test” (heterophile antibody), especially children.
-
Pre-transplant evaluations or when doctors need to confirm past EBV exposure.
-
Those with weakened immunity, where EBV activity may impact treatment.
Sample and preparation
-
Sample: Blood (serum)
-
Fasting: Not required
-
Timing: If your symptoms just started, antibodies may not show yet—repeat in 1–2 weeks if suspicion stays high.
Factors that may influence results
-
Testing too early → possible false-negative.
-
Weakened immune system → delayed or reduced antibody response.
-
Different labs use different units and cutoffs.
-
Borderline results may require repeat testing or more markers.
Practical guidance
-
Negative and feeling well: No action usually needed.
-
Negative but symptomatic: Full EBV panel or repeat test may help.
-
Equivocal: Retest in 1–2 weeks; consider additional markers.
-
Positive and well: Reflects past infection and is considered normal for most adults.
-
Positive with current symptoms: Pair with other tests (VCA-IgM, EBNA-IgG, EA-IgG, or PCR) to determine if the infection is recent or reactivated.
Disclaimer: This information is for educational purposes only and should not replace medical advice. Always review your test results with your healthcare provider to decide what they mean for you personally.
What does it mean if your EBV CAPSID Ag.ab/IgG result is too high?
A positive EBV VCA-IgG (≥ 22.0 U/mL) means you’ve been infected with Epstein–Barr virus (EBV) at some point in the past. This antibody typically remains positive for life, so most healthy adults have a positive result—this is common and expected. On its own, VCA-IgG does not prove a current/active infection.
To understand timing (recent vs. past) or reactivation, clinicians compare additional EBV markers and context:
-
VCA-IgM positive + EBNA-IgG negative → often consistent with a recent/acute infection.
-
VCA-IgM negative + EBNA-IgG positive → indicates a past infection, not active.
-
Reactivation is considered when VCA-IgG is positive with other findings (e.g., EA-IgG and/or EBV PCR) and compatible symptoms or immunosuppression.
Most of the time, a positive VCA-IgG alone just reflects prior exposure and doesn’t require treatment. If you currently have fatigue, fever, sore throat, or swollen lymph nodes, your clinician may add VCA-IgM, EBNA-IgG, ± EA-IgG or consider EBV PCR to clarify whether infection is recent.
Note: Reference ranges and units can vary by lab; always interpret your result alongside the range printed on your report and your clinical history.
Disclaimer: Educational only. Please review your results with your healthcare provider.
All Your Lab Results.
One Simple Dashboard.
Import, Track, and Share Your Lab Results Easily
Import, Track, and Share Your Lab Results
Import lab results from multiple providers, track changes over time, customize your reference ranges, and get clear explanations for each result. Everything is stored securely, exportable in one organized file, and shareable with your doctor—or anyone you choose.
Cancel or upgrade anytime
What does it mean if your EBV CAPSID Ag.ab/IgG result is too low?
Please refer to this interpretation chart:
| EBV CAPSID IgG | EBV CAPSID Igm | EBNA IgG | Interpretation |
| Negative | Negative | Negative | No previous exposure |
| Positive | Positive | Negative | Recent infection |
| Positive | Negative | Positive | Past infection |
| Positive | Negative | Negative | See note* |
| Positive | Positive | Positive | Past infection |
Note:
*Results indicate infection with EBV at some time (VCA IgG positive). However, the time of the infection cannot be predicted (ie, recent or past) since antibodies to EBNA usually develop after primary infection (recent) or, alternatively, approximately 5% to 10% of patients with EBV never develop antibodies to EBNA (past).
Laboratories
Bring All Your Lab Results Together — In One Place
We accept reports from any lab, so you can easily collect and organize all your health information in one secure spot.
Pricing Table
Gather Your Lab History — and Finally Make Sense of It
Finally, Your Lab Results Organized and Clear
Personal plans
$79/ year
Advanced Plan
Access your lab reports, explanations, and tracking tools.
- Import lab results from any provider
- Track all results with visual tools
- Customize your reference ranges
- Export your full lab history anytime
- Share results securely with anyone
- Receive 5 reports entered for you
- Cancel or upgrade anytime
$250/ once
Unlimited Account
Pay once, access everything—no monthly fees, no limits.
- Import lab results from any provider
- Track all results with visual tools
- Customize your reference ranges
- Export your full lab history anytime
- Share results securely with anyone
- Receive 10 reports entered for you
- No subscriptions. No extra fees.
$45/ month
Pro Monthly
Designed for professionals managing their clients' lab reports
- Import lab results from any provider
- Track lab results for multiple clients
- Customize reference ranges per client
- Export lab histories and reports
- Begin with first report entered by us
- Cancel or upgrade anytime
About membership
What's included in a Healthmatters membership
Import Lab Results from Any Source
See Your Health Timeline
Understand What Your Results Mean
Visualize Your Results
Data Entry Service for Your Reports
Securely Share With Anyone You Trust
Let Your Lab Results Tell the Full Story
Once your results are in one place, see the bigger picture — track trends over time, compare data side by side, export your full history, and share securely with anyone you trust.
Bring all your results together to compare, track progress, export your history, and share securely.
What Healthmatters Members Are Saying
Frequently asked questions
Healthmatters is a personal health dashboard that helps you organize and understand your lab results. It collects and displays your medical test data from any lab in one secure, easy-to-use platform.
- Individuals who want to track and understand their health over time.
- Health professionals, such as doctors, nutritionists, and wellness coaches, need to manage and interpret lab data for their clients.
With a Healthmatters account, you can:
- Upload lab reports from any lab
- View your data in interactive graphs, tables, and timelines
- Track trends and monitor changes over time
- Customize your reference ranges
- Export and share your full lab history
- Access your results anytime, from any device
Professionals can also analyze client data more efficiently and save time managing lab reports.
Healthmatters.io personal account provides in-depth research on 10000+ biomarkers, including information and suggestions for test panels such as, but not limited to:
- The GI Effects® Comprehensive Stool Profile,
- GI-MAP,
- The NutrEval FMV®,
- The ION Profile,
- Amino Acids Profile,
- Dried Urine Test for Comprehensive Hormones (DUTCH),
- Organic Acids Test,
- Organix Comprehensive Profile,
- Toxic Metals,
- Complete Blood Count (CBC),
- Metabolic panel,
- Thyroid panel,
- Lipid Panel,
- Urinalysis,
- And many, many more.
You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.
If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.
We implement proven measures to keep your data safe.
At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.