All tests › Inflammation and immune system

IgG4 subclass

Inflammation and immune system · also printed as IgG4, IgG subclass 4, Immunoglobulin G4, IgG 4, IgG4 level

Typical UK adult range0.08 to 1.4 g/L

Ranges vary between laboratories; the range printed on the report takes precedence.

What this test measures

IgG4 is the smallest subclass. A raised level is one of the features of IgG4-related disease, a condition that can inflame the pancreas, salivary glands and other organs. Subclasses are measured when the total IgG is normal but repeated infections suggest a gap in the immune response.

Why doctors request it

Requested by immunologists in recurrent chest and sinus infections, and IgG4 specifically when IgG4-related disease is being considered.

What commonly pushes it up

Infection or inflammation
IgG4-related disease and some allergic and parasitic conditions, for IgG4
Some antibody-producing conditions

What commonly pushes it down

An inherited or acquired subclass deficiency
Protein loss from the kidney or gut
Some immune-suppressing medicines as a class

Everyday reasons for a value outside the range

Values fluctuate with infections
A low subclass with normal vaccine responses is often of no consequence

About the sample

No fasting needed.

Written by a UK consultant physician. Typical UK adult reference ranges; your laboratory's own printed range takes precedence.

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This is an educational summary of results you uploaded. It is not medical advice, a diagnosis or a treatment plan, and it does not replace the doctor who requested the test. If you are worried, or a result is marked outside range, discuss it with your doctor. Written and reviewed by a UK consultant physician. Reference ranges vary between laboratories.