IgG (Immunoglobulin G)

Immunoglobulin G (IgG) is the most abundant antibody class in the bloodstream and forms the backbone of your long-term humoral immune response. This test measures the total concentration of IgG in a simple blood sample, typically using an immunoturbidimetric or ELISA-based method, and is used to assess immune competence, monitor disease activity, and support the investigation of autoimmune and inflammatory conditions.

It is suitable for patients with recurrent or unusual infections, those being investigated for autoimmune conditions such as lupus or rheumatoid arthritis, individuals with suspected immunoglobulin deficiencies, and anyone requiring monitoring of immune function before or during treatment with immunosuppressive or biologic therapies.

What is measured

• Total IgG: The overall level of immunoglobulin G in the blood, reflecting the body's capacity for antibody-mediated immunity. Abnormal levels can indicate immune deficiency, chronic infection, or an overactive immune response.

Why it matters

IgG is central to your body's ability to remember and neutralise pathogens. Low levels may point to an underlying immunodeficiency, while elevated levels can signal chronic inflammation, persistent infection, or autoimmune activity. Measuring IgG gives your clinician a clear, quantitative window into your immune status, helping to guide diagnosis, treatment decisions, and ongoing monitoring.

• Immunoglobulin G (IgG)

No special preparation required.

For blood tests, we recommend drinking plenty of water beforehand to ensure smooth sample collection. If you are taking any regular medication, continue to do so unless advised otherwise by your doctor.