Reference Values

≤0.90 ISR

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0.90 ISR or less            Negative - No Significant Level of IgM antibody to varicella-zoster detected.

0.91 - 1.09 ISR             Equivocal - Repeat testing in 10-14 days may be helpful.

1.10 ISR or greater        Positive - Significant level of IgM antibody to varicella-zoster virus detected, which may indicate current or recent infection. However, low levels of antibodies may occasionally persist for more than 12 months post-infection.

While the presence of IgM antibodies suggest current or recent infection, low levels of IgM antibodies may occasionally persist for more than 12 months post-infection.

The detection of antibodies to varicella-zoster in CSF may indicate central nervous system infection. However, consideration must be given to possible contamination by blood or transfer of serum antibodies across the blood-brain barrier.