IgG (Immunoglobulin G)
IgG makes up around three quarters of the antibodies in blood. After an infection or vaccination, IgG maintains protection against that specific microbe. A total IgG test does not show what you are immune to; it shows how much antibody you produce overall, which is what matters when immune deficiency is suspected.
Why Test Immunoglobulin G?
The test is used when recurrent or unusually severe infections suggest an immune deficiency, particularly repeated pneumonia or sinus infections, and to follow known deficiency. It is also used when conditions causing protein loss, or treatments that suppress the immune system, may have lowered antibody levels.
What Do High Immunoglobulin G Levels Mean?
A raised total IgG is seen with chronic infection, liver disease, and chronic inflammatory or autoimmune conditions. A markedly raised value produced by a single cell line can indicate a blood disorder such as myeloma, and is investigated with additional tests including protein electrophoresis.
What Do Low Immunoglobulin G Levels Mean?
A low IgG means reduced antibody production and a greater susceptibility to bacterial infection. Causes include primary immune deficiency, treatment with corticosteroids, immunosuppressants or rituximab, loss of protein through the kidneys or gut, and blood disorders. A low result with recurrent infections should be assessed by a doctor, as treatment with immunoglobulin replacement exists.
Symptoms to Watch For
- Recurrent infections, particularly of the airways and sinuses
- Pneumonia more than once
- Persistent diarrhoea
- Unexplained fever
- Unintended weight loss
- Infections that respond slowly to antibiotics
Who Should Get Tested?
- People with recurrent or unusually severe infections
- People suspected of having an immune deficiency
- People treated with immunosuppressive drugs
- People with conditions causing protein loss through the kidneys or gut
How to Prepare for Your Test
No special preparation is needed. Bring valid ID to your appointment.
Order Your Blood Test
Test your Immunoglobulin G levels with an accredited Swedish laboratory. Results within days, reviewed by Wellth.
Frequently Asked Questions
What is the difference between IgG, IgA and IgE?
Can low IgG be treated?
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Wellth Team
Wellth
Our content is written and reviewed by Wellth, and fact-checked against peer-reviewed research and current Swedish clinical guidelines.
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The information on this page is provided for informational purposes only and does not constitute professional medical advice, diagnosis, or treatment. Wellth provides health information and testing services but is not a substitute for clinical care. Always consult a qualified healthcare provider if you have questions about a medical condition. If you are experiencing severe or urgent symptoms, contact your doctor or call 1177 Vårdguiden. Blood test results should be interpreted by a qualified healthcare professional in the context of your complete medical history.