Description of the blood test:

Immunoglobulin G (IgG) is the most abundant type of antibody in the human body, accounting for approximately 75–80% of all antibodies in the bloodstream. While other antibodies (like IgM) react first to a new infection, IgG is produced later and provides long-term protection. These antibodies “remember” previous infections or vaccinations, allowing the immune system to react quickly if the same pathogen enters the body again. Additionally, IgG is the only class of antibodies that can cross the placenta, providing essential passive immunity to the fetus during pregnancy.

What Does the Test Represent?

• Goal: To measure the total level of IgG in the blood to evaluate long-term immunity and identify immune system disorders.
• Main Application: Diagnosing primary and secondary immunodeficiencies, monitoring chronic infections, and evaluating autoimmune or inflammatory conditions.
• Method: Immunoturbidimetry or Nephelometry.

Collection Recommendations (General)

• Timing: It is recommended to have blood drawn in the morning.
• Fasting: Overnight fasting (8–12 hours) is preferred; plain water is allowed.
• Material: Venous blood (serum).
• Specific Rules: Avoid intense physical stress and alcohol for 24 hours before the test. Inform your physician of any recent vaccinations or history of immunoglobulin therapy.

Factors Influencing the Result

• Factors Altering Levels: Chronic liver disease, severe malnutrition, or protein-losing conditions (like certain kidney or intestinal diseases) can significantly lower IgG levels.
• Medical Treatments: Recent treatment with corticosteroids or chemotherapy can suppress the production of IgG.
• Pregnancy: Maternal IgG levels may fluctuate as they are actively transported to the fetus.

When to Take This Test?

• Recommendations: If you have recurrent, severe, or unusual infections (pneumonia, sinusitis, skin infections), or if you are being evaluated for an autoimmune disease.
• Importance: Measuring total IgG is often the first step in determining if the body’s “memory” immune response is functioning correctly.

Medical Interpretation

• Crucial Note: The interpretation of total IgG levels is a complex clinical task. A normal total IgG level does not always guarantee health, as specific subclasses of IgG might still be deficient. Only a specialist can “fine-tune” these results by correlating them with your specific symptoms and medical history.
• High Levels (Hypergammaglobulinemia): Often seen in chronic infections (HIV, hepatitis), autoimmune diseases (Systemic Lupus Erythematosus, Rheumatoid Arthritis), or plasma cell disorders (like Multiple Myeloma).
• Low Levels (Hypogammaglobulinemia): Indicates a weakened immune system, which can be congenital (from birth) or acquired due to medications, kidney disease, or certain types of cancer.

Possible Further Investigations

• IgG Subclasses (1, 2, 3, 4): To identify specific deficiencies when the total IgG is normal but infections persist.
• IgA and IgM Levels: To assess the entire spectrum of the humoral immune response.
• Serum Protein Electrophoresis: To check for abnormal “peaks” of antibodies.
• Specific Antibody Titers: To see how well the immune system responds to specific vaccines (e.g., Tetanus or Pneumococcus).
• Consultation with an Immunologist or Infectious Disease Specialist.

When Does the Next Step Make Sense?

• If IgG levels are critically low, the next step may include immunoglobulin replacement therapy to prevent life-threatening infections. If levels are high, the focus shifts to identifying the source of chronic stimulation or ruling out a hematological malignancy.
• All clinical decisions must be made by a healthcare professional based on the presence of clinical symptoms and the results of additional immunological markers.

👉 If necessary, you can discuss the analysis results with a specialist such as an immunologist (Doctors – TAMC), or hematologist (Doctors – TAMC).