Herpeselect tests for antibodies present in your serum. Technically they are looking at surface proteins or markers and, by convention, distinguish them using letters. That's why you will see IgA, IgB, IgC...IgG... for example.
if your hsv1 igg is 5.10 that means that you are + for hsv1. typically most folks have hsv1 orally.
why did you get tested?
grace