Anyone know what IgG in blood test is?

It was part of my pre-natal testing, apparently that and my urine test could not be done properly for some reason. I saw it on my medical file when I moved. I can't find IgG on anything but I'm wondering if it some sort of STD testing, it came right before my HIV results.Anyone know what IgG in blood test is?
it's an immunoglobulin (antibody) which forms in response to an infection...
when you catch a cold (some bacterial infection) IgM increases first (it's the first response antibody, if you will), after awhile IgG increases to help fight the infection.
It should not have anything to do with your prenatal tests, other than checking if you're not sick now or if you have some immune defect. Most likely nothing to worry about
IgG is Immunoglobulin G and if my husband were awake, he could tell me just exactly what aspect of the immune system that's from and how it affects health. I think elevated IgE, however, means you're having an allergic reaction. At any rate, it's a measure of immune function.