An 8 year old girl was diagnosed with Mono in June. The EBV Ab VCA,IgG level was 3,186. In October she had the same test done and it came back with a level of 2,654. She was also diagnosed with MS in March or so. How long does your immune system stay down for and what should the next step be as far as testing? Also what would cause her levels to be so high. I was told that 120 is positive for mono. Any advice would be helpful and appreciated.