A high result on a Herpes Simplex Virus type 2 (HSV-2) Immunoglobulin G (IgG) test indicates that the immune system has produced a lasting response to the virus. This blood test detects IgG antibodies, which are long-term memory proteins that circulate after an infection has been established. The presence of these antibodies confirms a past or current infection with HSV-2, the virus primarily associated with genital herpes. A high index value suggests an established infection but does not indicate when the infection occurred or if an active outbreak is present. This diagnosis allows for informed decisions regarding personal health and transmission prevention.
Interpreting the High Index Value
The HSV-2 IgG test result is reported as an index value, which numerically represents the concentration of antibodies detected. This index compares the antibody level in the sample to a laboratory cutoff value, often 1.1. A result above this cutoff is considered positive, and a “high” index value is significantly above this minimum threshold.
A high index value primarily relates to the reliability of the diagnosis. Low-positive results, typically between 1.1 and 3.5, carry a higher risk of being a false positive. For these low values, a confirmatory test, such as the Western Blot, is often recommended to ensure accuracy.
A high index value, usually greater than 3.5 or 5.0 depending on the assay, suggests a robust immune response and high confidence in the positive diagnosis. The large quantity of antibodies makes a false positive due to cross-reactivity (e.g., with HSV-1) much less likely. This elevated number indicates the body has had ample time to produce significant IgG antibodies, often correlating with a longer duration of infection. However, the index value cannot predict the severity of future outbreaks or the frequency of viral shedding.
The Nature of HSV-2 Infection
Confirmation of HSV-2 antibodies establishes that the virus has entered the body and initiated a lifelong infection. HSV-2 is a DNA virus that efficiently establishes a persistent state. Transmission occurs through intimate contact with mucosal surfaces or abraded skin, typically during sexual activity, even when no sores are visible.
After initial infection, the virus travels along nerve pathways to the sacral ganglia, bundles of nerve cells near the base of the spine. Here, the virus establishes latency, remaining dormant within the nerve cells for the life of the individual. The virus can periodically reactivate and travel back down the nerves to the skin or mucosal surface.
This reactivation results in viral shedding, the release of the virus onto the skin surface. Most transmissions occur during asymptomatic shedding, meaning the virus can be transmitted even without visible lesions. While HSV-2 is usually associated with genital infection, many people with a positive IgG test are asymptomatic carriers who may never experience a recognizable outbreak. Outbreaks, when they occur, typically present as blisters or sores in the genital area.
Treatment Options and Ongoing Care
A positive HSV-2 IgG test result requires managing the infection through treatment. Antiviral medications, such as acyclovir, valacyclovir, and famciclovir, interfere with the virus’s ability to replicate its DNA. These medications do not eliminate the latent virus but reduce the frequency and severity of outbreaks.
Episodic Therapy
Episodic therapy involves taking a short course of antiviral medication only when an outbreak occurs or when early symptoms, like tingling or itching, begin. Starting this treatment early can shorten the duration of the lesions and decrease their severity.
Suppressive Therapy
Suppressive therapy involves taking a lower dose of antiviral medication every day, regardless of symptoms. This daily regimen is highly effective at reducing the frequency of outbreaks by 70% to 80% and is recommended for individuals who experience frequent recurrences. Suppressive therapy also significantly reduces asymptomatic viral shedding, lowering the risk of transmission to a sexual partner.
The diagnosis also necessitates careful attention to transmission prevention. Using barrier methods consistently, such as condoms, and avoiding sexual contact during any active outbreak significantly reduces transmission risk. Open communication with partners about the infection status is an important step in responsible management.