immunoglobulin g high levelselevated immunoglobulin g levelslow immunoglobulin g serumelevated immunoglobulin gimmunoglobulin g serum highimmunoglobulin g reference rangeimmunoglobulin g normal rangeimmunoglobulin g blood testimmunoglobulin g qn serum highimmunoglobulin g qn serum elevatedimmunoglobulin gimmunoglobulin g subclass 1