The detection of antibodies to rubeola 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. 13.4 AU/mL or less Negative - No significant level of IgG antibody to measles (rubeola) virus detected. 13.5-16.4 AU/mL Equivocal - Repeat testing in 10-14 days may be helpful. 16.5 AU/mL or greater Positive - IgG antibody to measles (rubeola) detected, which may indicate a current or past measles (rubeola) infection.