What titers (antibody tests) are used to check for a current or recent Herpes Zoster (shingles) infection?

From the Guidelines

To check for a current or recent shingles infection, the most appropriate laboratory test is the Varicella-Zoster Virus (VZV) IgM and IgG antibody titers. When considering the diagnosis of shingles, it is crucial to prioritize tests that offer high sensitivity and specificity. The latex agglutination (LA) test and ELISA are commonly used to detect varicella IgG antibody after natural varicella infection, as noted in the study by 1. However, for diagnosing current or recent shingles infection, VZV IgM and IgG antibody titers are more relevant. A positive VZV IgM antibody test indicates a current or recent infection, while IgG antibodies typically indicate past infection or immunity. Key points to consider in the diagnosis include:

• The characteristic shingles rash, which is painful, unilateral, and vesicular, following a dermatome
• The use of PCR testing of vesicular fluid from active lesions, which is more sensitive and specific than antibody testing when lesions are present
• The timing of testing, as IgM antibodies typically appear within the first week of infection and may persist for several weeks, while IgG levels rise more slowly but remain elevated long-term These considerations help distinguish shingles from other conditions with similar presentations and guide appropriate antiviral treatment decisions. It's also important to note that while the study by 1 discusses the use of LA test and ELISA for detecting varicella IgG antibody, the focus for shingles diagnosis should be on VZV IgM and IgG antibody titers for current or recent infection.

From the Research

Titers to Check for Current or Recent Shingles Infection

To determine if a person has a current or recent shingles infection, several types of antibody titers can be measured, including:

• Immunoglobulin M (IgM) antibodies, which are typically present early in the infection and indicate a recent exposure to the varicella-zoster virus (VZV) 2
• Immunoglobulin G (IgG) antibodies, which are present later in the infection and indicate a past exposure to VZV 2
• Immunoglobulin A (IgA) antibodies, which have been found to be elevated in patients with herpes zoster (shingles) 3

Measurement of Antibody Titers

The measurement of antibody titers can be done using various methods, including:

• Solid-phase radioimmunoassay, which can detect both IgM and IgG antibodies to VZV 2
• Indirect immunofluorescence, which can detect IgG antibodies to VZV 2
• Nucleic acid programmable protein array (NAPPA), which can detect IgG antibodies to various VZV proteins 4
• Enzyme-linked immunosorbent assay (ELISA), which can detect IgA and IgG antibodies to VZV 3

Interpretation of Results

The interpretation of antibody titer results can be complex and depends on various factors, including:

• The type of antibody measured (IgM, IgG, or IgA)
• The level of antibody titer (e.g., high, low, or undetectable)
• The clinical presentation of the patient (e.g., symptoms, disease severity)
• The timing of sample collection (e.g., acute phase, convalescent phase) 3 A four-fold or higher increase in VZV IgG antibody titer between acute and convalescent phase sera can indicate a current or recent shingles infection 3. However, the diagnostic usefulness of VZV-specific IgA and IgG antibodies in patients with herpes zoster is still being researched, and more studies are needed to fully understand their role in diagnosis 3.