HSV-2 Ab IgG: What Your Result Means, Index Value Ranges & False Positive Risk

Sample type: Serum

Other names: HSV-2 Ab IgG, HSV-2 IgG, HSV 2 IgG, HSV 2 Ab IgG, HSV-2 Ab IgG, Herpes Simplex Virus 2 IgG, Herpes Simplex 2 Ab IgG, Herpes Simplex Virus Type 2 IgG, HSV-2 IgG Antibody, HSV 2 Antibody IgG, HSV II IgG, Herpes II IgG, HSV-2 Ab IgG Reactive, HSV 2 IgG EIA, HSV-2 IgG EIA, HSV-2 IgG Ab Index, HSV 2 IgG Index, HSV 2 Ab IgG Qn IA Serum, Herpes 2 IgG, Herpes Type 2 IgG, Herpes Simplex II IgG, Roche Elecsys HSV-2 IgG, Biokit HSV-2, WarningAbnormal HSV 2 IgG, HSV-2 Seropositive, HSV 2 Seropositive, HSV IgG Stark Erhöht (German), HSV 2 IgG Positif (French), HSV 2 IgG Positivo (Spanish/Portuguese), IgG HSV 2 Positif Artinya (Indonesian), Apakah HSV 2 Berbahaya (Indonesian), تحليل HSV-2 IgG (Arabic), Герпес 2 Типа IgG (Russian)

Optimal result: 0 – 0.91 / index

Written May 24, 2026

Updated August 31, 2026

By Healthmatters Editorial Team

Peer-reviewed sources

A positive HSV-2 IgG result (index ≥ 1.10) indicates prior exposure to herpes simplex virus type 2. Most people with a positive result have mild or no symptoms.

The index value matters: Low positive results (1.10–3.49) have a significant false positive rate — up to 50% in low-risk populations. If your result is in this range and you have no history of symptoms, a confirmatory Western blot test is strongly recommended before drawing clinical conclusions.

High positive results (≥ 3.50, and especially very high values like 8, 23, 40+) are more likely to represent true infection. However, a high number does not indicate greater severity, more frequent outbreaks, or higher contagiousness compared to a lower positive value.

HSV-2 is a common, manageable chronic infection. Effective antiviral treatments exist. A positive test is not a medical emergency.

The HSV-2 Ab IgG test detects IgG-class antibodies to herpes simplex virus type 2 in blood. A negative result (<0.90 index) means no prior exposure detected. A positive result (≥1.10) indicates past infection — though low positive results (1.10–3.49) carry a significant false positive rate and may require confirmatory testing. Most people with a positive HSV-2 IgG test have either mild or no symptoms.

QUICK ANSWER

The HSV-2 Ab IgG test measures IgG antibodies to herpes simplex virus type 2 (HSV-2). A positive result means your immune system has encountered HSV-2 at some point — it does not mean you have an active outbreak or that you will necessarily develop symptoms.

Negative: index < 0.90. Equivocal: 0.90–1.09. Positive: ≥ 1.10.

The most important clinical nuance: low positive results (index 1.10–3.49) have a high false positive rate — up to 50% in some low-risk populations. A result in this range does not definitively confirm HSV-2 infection and may warrant a confirmatory Western blot test.

Key takeaway: A positive HSV-2 IgG result — especially a low positive — does not necessarily mean you have HSV-2. Many people with low positive results in the 1.10–3.49 range do not have the infection. Higher index values (>3.50) are more likely to represent true infection. Many people with confirmed HSV-2 have never had symptoms and live normal, healthy lives with or without antiviral treatment.

WHAT DOES MY HSV-2 INDEX VALUE MEAN? (1.1, 3.5, 8, 23, 40+)

The HSV-2 IgG result is reported as an index value — a ratio comparing your antibody level to a calibrator. Different assays use slightly different scales, but the most common (HerpeSelect ELISA, manufactured by Focus Diagnostics/Bio-Rad) uses:

Index value	Result	What it means
< 0.90	Negative	No HSV-2 antibodies detected; prior exposure unlikely
0.90–1.09	Equivocal	Indeterminate — may be a very early infection or a low-level false positive; repeat in 4–6 weeks recommended
1.10–3.49	Low positive	HSV-2 antibodies detected; false positive rate is significant (up to 50% in low-risk populations); confirmatory testing recommended
≥ 3.50	High positive	More likely to represent true HSV-2 infection; confirmatory testing still recommended if clinically uncertain

Reference ranges vary by assay. The Roche Elecsys HSV-2 IgG assay uses a different cutoff (reactive: index ≥ 1.1, but the false positive pattern is similar at low values). Always check your specific lab report's reference range.

What specific numbers mean:

Index value of 8.0, 23, 40, or similar high numbers: High positive — strongly suggests true HSV-2 infection. These values are far above the cutoff and are unlikely to be false positives.
Index value of 1.1–3.5: Low positive — requires confirmatory testing before a definitive diagnosis.
Index value of 0.91: Equivocal — borderline result, repeat recommended.
"< 0.90" or "0.90" on your report: Negative — no antibodies detected. A result of 0.90 is at the boundary and may be reported as equivocal by some labs; a result of 0.108 or similar very low numbers is clearly negative.

WHAT DOES A HIGH HSV-2 IgG MEAN?

A positive or high HSV-2 IgG result means IgG antibodies to HSV-2 were detected — indicating prior exposure to the virus. This does not mean you have an active infection right now. IgG antibodies develop 2–6 weeks after initial infection and persist lifelong.

How long after exposure does HSV-2 IgG turn positive?

Time after exposure	Test accuracy
< 2 weeks	Usually negative — antibodies not yet detectable
2–6 weeks	Some infections detectable; sensitivity still limited
6–12 weeks	Most people with true infection will be detectable
12–16 weeks	Most accurate window — sensitivity reaches 80–98%
> 16 weeks	Reliable. A negative result at this point is highly reassuring.

The CDC recommends retesting 12 weeks after a potential exposure if an initial test is negative.

"Positive" does not mean:

You currently have symptoms
You will definitely develop outbreaks
You acquired the infection recently
The result is a medical emergency

What a positive result does indicate:

Prior exposure to HSV-2 at some point in your life
Your immune system has produced antibodies in response
You may be able to transmit the virus, including during periods without symptoms (asymptomatic shedding)

Why is my HSV-2 IgG so high? The index value does not directly reflect how long you've been infected, how many outbreaks you've had, or how contagious you are. A very high index value (40, 58, 23, etc.) means a strong antibody response — this is common in long-established infections and does not indicate a more dangerous or more severe form of the disease compared to lower values.

Is a positive HSV-2 IgG result dangerous? HSV-2 is a common, manageable chronic infection. It is not life-threatening for immunocompetent adults. The Centers for Disease Control estimates that approximately 11% of people aged 14–49 in the United States have HSV-2. The majority of people with HSV-2 have never been diagnosed because their symptoms are mild, absent, or mistaken for other conditions. A positive HSV-2 IgG test is not a medical emergency and does not mean you are in danger.

THE FALSE POSITIVE PROBLEM: WHAT YOU NEED TO KNOW

This is the most clinically important section of this page, and the most absent from standard consumer health content.

The HerpeSelect IgG ELISA (the most commonly used HSV-2 blood test in the US) has a significant false positive rate at low index values.

Published research and CDC guidance have documented:

In low-risk populations, up to 50% of results in the 1.10–3.49 range may be false positives
The false positive rate drops substantially above index 3.50 — high positive results are more reliable
The Roche Elecsys assay has better specificity at low values but is not immune to false positives

What causes a false positive HSV-2 IgG result?

Cross-reactivity with HSV-1 antibodies (if you have oral herpes/cold sores, this can occasionally trigger a low positive HSV-2 result)
Cross-reactivity with other herpesviruses (varicella zoster, CMV, EBV) — though this is less common with type-specific assays
Rheumatological conditions (lupus and other autoimmune conditions have been associated with false positive HSV-2 IgG)
Technical laboratory variation at borderline values
Biological variation in individuals with high background antibody activity

Does a yeast infection cause a false positive HSV-2 test? No — yeast infections do not affect blood antibody tests. The false positive issue is specifically about cross-reactive antibodies at low index values, not about concurrent infections.

Can chickenpox (varicella zoster) cause a false positive? Occasionally, at low index values — varicella zoster is a herpesvirus and there can be some cross-reactivity. This is uncommon with type-specific IgG assays but has been reported.

WHAT IS THE WESTERN BLOT AND WHY DOES IT MATTER?

The University of Washington Western blot (UW WB) is the gold standard confirmatory test for HSV-2 and is more accurate than the standard EIA/ELISA blood test, particularly for low positive results.

When to consider a Western blot:

Low positive IgG result (index 1.10–3.49) without a history of symptoms
Equivocal result (0.90–1.09) that needs clarification
Result doesn't match clinical history (e.g. long-term monogamous relationship with a partner who tests negative)
You want the highest possible accuracy before making decisions about treatment, disclosure, or relationships

How to get a Western blot: The University of Washington Western blot is available through ordering physicians via UWMC. It is not widely available through routine commercial labs but can be ordered by your clinician. Some specialist sexual health clinics can facilitate testing. The Biokit rapid point-of-care test is another alternative for confirmation.

Important: A Western blot is not needed if your index value is high (>3.50) and you have a clinical history consistent with HSV-2. It is most valuable for resolving low positive results.

What is the HSV-2 IgG inhibition assay? The IgG inhibition assay ("HSV-2 IgG Inhibition IA" or "HSV-2 IgG Inhibition, IA Out of Range") is a supplemental confirmatory test offered by some commercial labs as a reflex for low positive HerpeSelect results. It confirms whether detected antibodies are genuine HSV-2 antibodies or a false positive signal. If your lab report specifically shows "HSV-2 IgG Inhibition IA," see the dedicated HealthMatters page: HSV-2 IgG Inhibition IA. The inhibition assay is considered less definitive than the Western blot — the UW Western blot remains the gold standard for resolving ambiguous results.

ASYMPTOMATIC HSV-2: WHAT YOU NEED TO KNOW

Many people with a positive HSV-2 IgG test have never had a recognisable outbreak and may never develop one. Studies estimate that approximately 80% of people with HSV-2 are unaware of their infection.

What "no symptoms" means:

Symptoms may have been very mild and mistaken for a rash, ingrown hair, or minor irritation
Subclinical shedding occurs — virus can be transmitted without visible sores
Some people genuinely remain asymptomatic throughout their lives

Asymptomatic shedding: Even without symptoms, HSV-2 can shed and be transmitted. Asymptomatic shedding is more common in the first year after acquisition and decreases over time. Daily antiviral therapy (suppressive therapy with valacyclovir or acyclovir) significantly reduces shedding and transmission risk.

IgG vs IgM: WHAT'S THE DIFFERENCE?

	HSV-2 IgG	HSV-2 IgM
What it indicates	Past infection / prior exposure	Possibly recent/acute infection — but less reliable
When it appears	2–6 weeks after initial infection; persists lifelong	Appears early but also recurs with reactivation
Reliability	More reliable for confirming past exposure	Less reliable — IgM can be positive in recurrent infection and has high false positive rates
Used for	Serostatus screening, sexual health decisions	Rarely used clinically; not recommended for routine diagnosis

IgM caveats: HSV-2 IgM is not a reliable indicator of acute or recent infection. IgM can be positive during recurrent outbreaks (not just new infections), can cross-react with HSV-1, and has a high false positive rate. Most guidelines do not recommend HSV IgM testing for clinical decision-making.

"WARNINGABNORMAL" ON YOUR LAB REPORT

Some lab reports display "WarningAbnormal" or "WARNINGABNORMAL" before the test name when a result falls outside the reference range — for example: "WarningAbnormal HSV 2 IgG, Type Spec." This is a standard lab reporting flag meaning the result is outside normal limits. It does not indicate severity or urgency beyond the result value itself. Interpret the result using the index value and reference range, not the flag.

WHAT SHOULD I DO AFTER MY HSV-2 IgG RESULT?

Your result	What it means	Recommended next step
< 0.90	Negative — no HSV-2 antibodies detected	No action needed. If a potential exposure was less than 12–16 weeks ago, retest at 12–16 weeks.
0.90–1.09	Equivocal — borderline	Repeat the test in 4–6 weeks. Do not treat as a diagnosis.
1.10–3.49	Low positive — significant false positive rate	Request confirmatory testing: HSV-2 IgG Inhibition Assay (Quest reflex) or University of Washington Western blot. Do not make treatment or disclosure decisions on this result alone.
≥ 3.50	Positive — more likely true infection	Discuss with your clinician: symptoms, transmission risk, suppressive therapy options. If asymptomatic, treatment is optional but suppressive therapy reduces shedding.

MANAGEMENT AND TREATMENT

If you have a confirmed positive HSV-2 IgG:

A positive HSV-2 IgG does not require treatment if you have no symptoms. However, options include:

No treatment: Many people with asymptomatic or mild HSV-2 choose not to take antiviral medication. The infection is chronic but manageable.
Episodic therapy: Taking antiviral medication (acyclovir, valacyclovir, famciclovir) at the start of an outbreak to shorten duration and severity.
Suppressive therapy: Daily antiviral medication to reduce outbreak frequency, asymptomatic shedding, and transmission risk to partners. Recommended for those with frequent outbreaks or who have seronegative partners.

Common antivirals: Valacyclovir (Valtrex) 500mg daily is the most commonly prescribed suppressive therapy. Acyclovir 400mg twice daily is an alternative.

INTERNAL LINKS

If your lab report says "HSV 2 IgG, Type Spec" specifically, see the dedicated page: HSV-2 IgG Type Spec

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Frequently Asked Questions

What does a positive HSV-2 IgG mean?

A positive HSV-2 IgG result (index ≥ 1.10) means IgG antibodies to herpes simplex virus type 2 were detected, indicating prior exposure to the virus. It does not mean you have an active outbreak, and many people with positive results have never had recognisable symptoms. Low positive results (1.10–3.49) may be false positives and require confirmatory testing.

What is the normal range for HSV-2 IgG?

The standard reference range for HerpeSelect IgG ELISA is: negative = index < 0.90; equivocal = 0.90–1.09; positive = ≥ 1.10. Results above 3.50 are considered high positive. Reference ranges vary between assays and labs — always check the range on your specific report.

What does "HSV-2 test results range high positive" mean?

High positive means your index value is well above the cutoff (typically ≥ 3.50, though some labs set higher thresholds). A high positive result is more likely to represent true HSV-2 infection than a low positive. The specific number does not indicate disease severity — a result of 40 is not clinically more dangerous than a result of 8.

What is the HSV-2 IgG false positive rate?

For HerpeSelect IgG ELISA, the false positive rate for results in the 1.10–3.49 range is estimated at up to 50% in low-risk populations. This is well-documented in published literature and acknowledged by the CDC. Results above 3.50 have a much lower false positive rate. If your result is in the low positive range without a history of symptoms, a confirmatory Western blot test is recommended.

Why is my HSV-2 IgG so high?

A high index value (8, 23, 40, or higher) reflects a strong antibody response to HSV-2. This is common in long-established infections and does not indicate a more dangerous or more contagious form of the virus. Index values are not a direct measure of viral load, outbreak frequency, or transmission risk.

Is HSV-2 IgG positive dangerous?

HSV-2 is a common, manageable chronic infection — it is not life-threatening for immunocompetent adults. Approximately 11% of people aged 14–49 in the US have HSV-2. Most never have a diagnosed outbreak. Effective antiviral treatments exist that reduce outbreak frequency and transmission risk. A positive HSV-2 IgG test is not a medical emergency.

What does "HSV-2 nothing to worry about" mean — is that true?

For most healthy adults, HSV-2 is a manageable condition that does not significantly impact quality of life or overall health. The main considerations are: transmission risk to uninfected partners (manageable with antivirals and consistent condom use), and risk to newborns if a mother has active HSV-2 at time of delivery (discuss with your OB if pregnant). For immunocompromised individuals, more aggressive management may be warranted.

What is the difference between HSV-2 IgG and IgM?

IgG antibodies persist lifelong and indicate past exposure. IgM antibodies appear early in infection but are not reliable — they can be positive during recurrent outbreaks (not just new infections), cross-react with HSV-1, and have high false positive rates. Most guidelines do not recommend HSV IgM for clinical decision-making. IgG is the standard test for HSV-2 serostatus.

What does "WarningAbnormal HSV 2 IgG, Type Spec" mean on my lab report?

"WarningAbnormal" is a standard lab reporting flag indicating the result is outside the normal reference range. It does not indicate a medical emergency — it simply means the result is positive (above 0.91 index). Interpret the result using the index value and the reference range printed on your report.

What is the Western blot test for HSV-2 and when do I need it?

The University of Washington Western blot is the most accurate test for HSV-2 and is recommended as confirmatory testing for low positive IgG results (index 1.10–3.49) — particularly when there is no history of symptoms. It is significantly more specific than the standard ELISA and can resolve equivocal or low positive results. Ask your doctor about ordering it if your IgG result is low positive.

What does "HSV 2 IgG, Type Spec" mean?

"Type Specific" indicates the test uses type-specific antigens (glycoprotein G, or gG-2) to detect antibodies specifically to HSV-2, rather than detecting antibodies that could cross-react with HSV-1. This makes it more accurate than older non-type-specific tests. Most modern HSV-2 IgG tests are type-specific.

Can you have HSV-2 antibodies but no infection?

Yes — low positive results (index 1.10–3.49) may be false positives due to cross-reactivity or assay limitations. Additionally, a small number of people may develop antibodies without ever having clinically apparent infection. Confirmatory Western blot testing is recommended before making any clinical decisions based on a low positive result alone.

Can HSV-2 antibodies decrease over time?

Yes — HSV-2 IgG antibody levels can fluctuate over time and may decrease, particularly in people with infrequent or no outbreaks. In some cases, very long-standing infections with no recent reactivation may show declining antibody levels that occasionally approach the equivocal range. However, a single test showing a lower value than a previous one does not mean the infection has resolved — HSV-2 is a lifelong infection. Antibody levels are not a reliable measure of infectivity or disease activity.

How long does it take for HSV-2 to show up on a blood test?

IgG antibodies typically become detectable 2–6 weeks after initial infection, though in some people it can take up to 3–6 months to reach reliable detection levels. The standard recommendation is to test at least 12–16 weeks after a potential exposure for the most accurate result.

Clinical Sources & References

All our content is backed by peer-reviewed studies, academic research, and trusted medical sources. We’re committed to accuracy and transparency — see our editorial policy for details.

Serological testing for herpes simplex virus (HSV)-1 and HSV-2 infection

Clin Infect Dis. · 2002 View source ↗
Diagnosis of genital herpes simplex virus infection in the clinical laboratory

Virol J. · 2014 View source ↗
Serologic Screening for Genital Herpes: An Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

JAMA. · 2016 View source ↗
Diagnosis and Management of Genital Herpes: Key Questions and Review of the Evidence for the 2021 Centers for Disease Control and Prevention Sexually Transmitted Infections Treatment Guidelines

Clin Infect Dis. · 2022 View source ↗
Infectious co-factors in HIV-1 transmission herpes simplex virus type-2 and HIV-1: new insights and interventions

Curr HIV Res. · 2012 View source ↗

Article Review Log

Last reviewed May 24, 2026

Originally published May 24, 2026

Reviewed by HealthMatters Editorial Team

Written by Healthmatters Editorial Team

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HSV-2 Ab IgG: What Your Result Means, Index Value Ranges & False Positive Risk

QUICK ANSWER

WHAT DOES MY HSV-2 INDEX VALUE MEAN? (1.1, 3.5, 8, 23, 40+)

WHAT DOES A HIGH HSV-2 IgG MEAN?

THE FALSE POSITIVE PROBLEM: WHAT YOU NEED TO KNOW

WHAT IS THE WESTERN BLOT AND WHY DOES IT MATTER?

ASYMPTOMATIC HSV-2: WHAT YOU NEED TO KNOW

IgG vs IgM: WHAT'S THE DIFFERENCE?

"WARNINGABNORMAL" ON YOUR LAB REPORT

WHAT SHOULD I DO AFTER MY HSV-2 IgG RESULT?

MANAGEMENT AND TREATMENT

INTERNAL LINKS

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Frequently Asked Questions

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