IgG subclass 1
What it measures, and what changes the number.
IgG is divided into four subclasses that differ slightly in structure and function. IgG subclass 1 (IgG1) is the largest of the four and makes up most of total IgG. It is mainly involved in responses to protein antigens, such as many viral proteins and toxins.
It is measured together with the other three subclasses and total IgG, since the subclasses are interpreted as a set and their sum is compared with the total IgG result. Total IgA is often measured at the same time.
Subclasses are measured by nephelometry or immunoassay, and different kits can give noticeably different results, so comparisons are most meaningful within the same laboratory. Expected values depend on age, particularly in childhood. Fasting is not usually required. Labs may print it as IgG1, IgG subclass 1 or Inmunoglobulina G subclase 1.
Often read alongside: IgG, IgG subclass 2, IgG subclass 4, IgA