IgG is the most abundant antibody in the body, making up about 70–80% of total immunoglobulins.

It provides long‑term immunity after infection or vaccination.

Clinical uses include:

Assessing immune system function.

Detecting past exposure to infections (e.g., Hepatitis, Rubella, COVID‑19).

Monitoring response to vaccines.

Diagnosing immunodeficiency disorders.

Supporting evaluation of chronic infections and autoimmune diseases.

Often performed alongside IgA, IgM, and IgE for a complete immunoglobulin profile.

Analyte: Serum IgG concentration (mg/dL).

Normal Range (varies by age and lab):

Adults: ~700–1600 mg/dL

Abnormal Findings:

Low IgG: Suggests immunodeficiency, protein‑losing conditions, or certain genetic disorders.

High IgG: May indicate chronic infections, autoimmune diseases (e.g., rheumatoid arthritis, lupus), or liver disease.

Clinical Use:

Provides a marker of long‑term immunity and immune health.

Helps guide diagnosis and management of immunodeficiency or autoimmune conditions.

Supports evaluation of chronic inflammatory and infectious diseases.