Can a Herpes Test Be a False Positive?

Most diagnoses for genital herpes are accurate, based on laboratory testing and an examination of the affected area. Some types of herpes testing are no longer advised, because they can lead to false-positive results.
  1. Immunoglobulin M (IgM) antibody testing

    • Immunoglobulin M (IgM) antibody testing was once a commonly recommended form of testing for herpes, because it could identify that infection with a human herpes virus had occurred.

    Current Recommendations

    • The American Social Health Association (ASHA) reports that the use of IgM antibody testing is no longer recommended for the diagnosis of herpes, because it cannot distinguish between genital herpes and cold sore infections. A positive result can even be triggered by other herpes viruses, such as varicella-zoster, which causes chicken pox and shingles.

    Immunoglobulin G (IgG) antibody testing

    • The ASHA recommends using immunoglobulin G (IgG) antibody testing instead of IgM antibody testing, as IgG testing can be used to identify which type of herpes virus has been contracted.

    Confirming a Diagnosis

    • Although IgG testing can pinpoint which type of herpes is present, it cannot actually show that genital herpes is present. Herpes simplex-2 virus, the genital herpes virus, can also infect the oral area, leading to cold sores. Therefore, according to the International Herpes Management Forum (IHMF), antibody testing is not enough to confirm a diagnosis.

    Other Testing

    • According to the IHMF, it is standard to take a sample from a herpes sore and have the sample either cultured or antigen-tested in order to show genital herpes infection.

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