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Varicella Zooster IgG
Bacterial/ Viral
Report in 48Hrs
At Home
No Fasting Required
Details
Detects IgG antibodies against VZV, the virus responsible for chickenpox and shingles
₹899₹1,540
42% OFF
Varicella Zoster IgG Test Information Guide
- Why is it done?
- Test Purpose: Detects IgG antibodies against varicella zoster virus (VZV), which causes chickenpox and shingles (herpes zoster). This test measures immunity to VZV, indicating past infection or vaccination.
- Primary Indications: Assess immunity status prior to vaccination, confirm previous chickenpox infection, screen pregnant women for susceptibility to VZV, evaluate immunocompromised patients, assess occupational exposure risk in healthcare workers, and determine need for post-exposure prophylaxis.
- Typical Timing: Pre-vaccination screening, pre-pregnancy counseling, pre-transplant evaluation, occupational health screening, and when determining susceptibility in exposed individuals. Can be performed at any time regardless of active infection status.
- Normal Range
- Reference Values: Negative or < 0.90 index/ratio (varies by laboratory method); positive or ≥ 0.90 index/ratio indicates immunity. Some labs report in IU/mL with cutoff typically around 150-200 IU/mL or higher.
- Result Interpretation: Positive (≥ 0.90): Immune to VZV from prior infection or vaccination; Negative (< 0.90): Susceptible to VZV and at risk for infection; Equivocal/Borderline (0.80-0.99): Repeat testing recommended as result is inconclusive.
- Units of Measurement: Index/ratio (most common), IU/mL (international units per milliliter), or mIU/mL. Laboratory-specific cutoff values apply; always reference the specific laboratory's reference range.
- Normal vs. Abnormal: Normal (positive IgG) means adequate immunity; Abnormal (negative IgG) indicates susceptibility and potential need for vaccination or post-exposure prophylaxis if exposed.
- Interpretation
- Positive IgG Result: Indicates immunity to varicella zoster virus from either prior chickenpox infection or successful vaccination. Person is protected against developing chickenpox. Generally lifelong immunity, though shingles can still occur later in life.
- Negative IgG Result: Indicates lack of immunity to VZV and susceptibility to infection. Vaccination is recommended unless contraindicated. Post-exposure prophylaxis with varicella zoster immunoglobulin (VZIG) or antivirals may be needed if exposure occurs.
- High Positive Results: Very high antibody levels may indicate recent infection or reactivation (shingles), particularly if combined with clinical symptoms or positive IgM. However, IgG alone does not distinguish recent from past infection.
- Factors Affecting Results: Immunosuppression (HIV/AIDS, chemotherapy, transplant) may result in falsely negative or low results; timing of testing (IgG appears 1-4 weeks after infection); laboratory methodology variations; recent vaccination status.
- Clinical Significance Patterns: IgG positive + IgM negative = past infection/immunity; IgG positive + IgM positive = recent or current infection; IgG negative = no prior exposure/not immune; IgG negative + symptomatic presentation = possible acute infection requiring follow-up IgM testing.
- Associated Organs
- Primary System Involved: Immune system and nervous system (peripheral and central). VZV affects dermatome distribution along sensory nerve paths and can cause disseminated disease affecting skin, lungs, liver, and central nervous system.
- Conditions Associated with Abnormal Results: Negative results: Varicella (chickenpox) susceptibility, need for vaccination. Positive results: Previous chickenpox or successful vaccination, potential for shingles reactivation in immunocompromised patients.
- Diseases Diagnosed or Monitored: Varicella (chickenpox), herpes zoster (shingles), disseminated varicella zoster, post-herpetic neuralgia, VZV encephalitis, VZV meningitis, VZV ophthalmicus (eye involvement), immunocompromised VZV infection.
- Potential Complications with Abnormal Status: If negative (non-immune): Severe chickenpox, pneumonia, encephalitis, secondary bacterial infection. If immunocompromised with positive history: Disseminated zoster, VZV meningitis, retinitis, severe post-herpetic neuralgia lasting months to years.
- Follow-up Tests
- Based on Negative IgG Results: Varicella vaccination (if not contraindicated); repeat IgG testing 4-6 weeks post-vaccination to confirm seroconversion; IgM testing if acute symptoms develop after exposure.
- Based on Positive IgG Results: If symptomatic: VZV IgM testing, PCR from vesicular fluid or lesions, viral culture; if immunocompromised: monitoring for reactivation; consider herpes zoster vaccination eligibility assessment.
- Further Investigations: In immunocompromised patients: CD4+ count (HIV), immunological panels; in pregnant women: repeat testing if initially negative; in exposed individuals: symptom monitoring with follow-up testing if symptoms develop.
- Monitoring Frequency: Post-vaccination: 1 test at 4-6 weeks; immunocompromised patients: baseline assessment only unless symptomatic; pre-pregnancy: single assessment; occupational screening: per institutional protocol (typically every 1-3 years).
- Complementary Tests: VZV IgM (acute infection), VZV PCR (active disease), direct fluorescent antibody testing (active lesions), herpes zoster antibody testing, complete blood count, CD4+ count (HIV patients).
- Fasting Required?
- Fasting Requirement: No - Fasting is NOT required for this blood test.
- Special Preparation Instructions: No special preparation needed. Patient may eat and drink normally. Can be performed at any time of day.
- Medications to Avoid: No medications need to be avoided. However, if receiving immunoglobulin therapy or blood transfusions, inform the healthcare provider as these may temporarily affect antibody results. Current antiviral therapy does not affect IgG testing.
- General Preparation: Bring valid identification and insurance card. Wear loose-fitting clothing for easy blood draw access. Inform phlebotomist of needle anxiety if present. Stay hydrated. Timing consideration: Allow 4-6 weeks after vaccination before testing to confirm immune response, or test immediately if assessing prior immunity status.
How our test process works!
