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Immunology Laboratory

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IgG Subclasses

Also known as: Gsub; IgG subsets; Subclasses; IgG4

IgG subclass levels vary with age. IgG2 levels are physiologically low in infancy and may not reach adult levels until 10 - 12yrs of age. The most common subclass deficiency is IgG2, may be associated with IgA deficiency. IgG4 concentrations can be increased in patients with IgG4 related systemic disease, parasitic infections and atopy. IgG3 deficiency may be found in patients with a history of upper respiratory tract infections.

Specimen requirements

Serum - 1ml


Price on application

Laboratory turnaround time

7 days

Laboratory method


Reference range/units

Adult reference range:
  • IgG1 = 3.80 - 9.30g/L
  • IgG2 = 2.40 - 7.00g/L
  • IgG3 = 0.20 - 1.80g/L
  • IgG4 = 0.04 - 0.86g/L

Validated to international standard CRM470 (The Binding Site).

For children age matched reference ranges are provided.

Associated tests

Not applicable

Sample stability

28 days at 2-8ÂșC

Shipping and storage

UK and Ireland

Ambient temperature and first class post. Hays DX users please enquire via email below.


Ambient temperature if courier will deliver within 72 hours otherwise consider refrigerated transport. Freezing is not a requirement.

Ensure delivery Monday to Friday 09:00 - 17:30.

Further information and contact details

For further information, email

Last reviewed:13 September 2022