Converting ISR to IU/ml

[Guest guest]

I will appreciate if somebody can write how to convert ISR to IU/ml

for antibody titers. My son's recent rubella (IgG) titer is in ISR

units (2.9 ref range > 1.09, done by Quest Diag) and the one we did

1.5 years back is in IU/ml (154 ref range > 10, done by Lab

corporation of America). The different units are making it difficult

for us to understand if the rubella IgG level has really gone down.

Thanks,

Dinesh

Madison, WI