Interpret Your Immunoglobulin G Results
Enter your IgG value below and get an instant, free AI interpretation — a plain-English explanation checked against WHO/IFCC reference ranges.
Medical Disclaimer
This AI-generated interpretation is for educational purposes only and does not constitute medical advice, diagnosis, or treatment. Results may vary based on individual health factors not captured here.
Always consult a qualified healthcare professional before making any health decisions. Read full disclaimer →
Immunoglobulin G Normal Ranges
IgG is the most abundant immunoglobulin in blood, comprising approximately 75% of total immunoglobulins.
| Age Group | Reference Range | Unit | Notes |
|---|---|---|---|
| Adults (18–64) | 700 – 1600 | mg/dL | — |
| Children / Pediatric | 400 – 1200 | mg/dL | Age-dependent; rises through childhood |
Also reported in: g/L.
Why Doctors Order the Immunoglobulin G Test
Low IgG (hypogammaglobulinemia) causes increased susceptibility to bacterial infections, especially recurrent sinusitis, pneumonia, and otitis media from encapsulated bacteria (Streptococcus pneumoniae, Haemophilus influenzae). The most common cause in adults is Common Variable Immunodeficiency (CVID).
How to Enter Your IgG Result
Immunoglobulin G can be reported in mg/dL or g/L. Choose the unit printed next to your result on the lab report so it is compared with the matching reference range.
Reference ranges for IgG differ by age group, so entering your age gives a more accurate reading.
What a Low or High IgG Can Be Associated With
Below the reference range
- Common Variable Immunodeficiency (CVID) — most common primary immunodeficiency in adults
- X-linked agammaglobulinemia (XLA) — severe congenital B cell deficiency
- Secondary immunodeficiency: CLL, lymphoma, post-rituximab therapy, high-dose steroids
- Protein-losing enteropathy or nephrotic syndrome (loss of IgG)
- Physiological nadir in infants (3–6 months): maternal IgG depleted, own production not yet established
Above the reference range
- Chronic infections (tuberculosis, HIV, hepatitis C, osteomyelitis)
- Autoimmune liver disease (autoimmune hepatitis, primary biliary cholangitis)
- IgG multiple myeloma (monoclonal — paraprotein spike on SPEP)
- Connective tissue diseases (SLE, RA)
- Polyclonal hypergammaglobulinemia (chronic inflammation, liver disease)
These are common associations, not a diagnosis. A single result is read alongside your symptoms, history and other tests — discuss it with your doctor.
What Can Change Your IgG Result
Before you read too much into a result, consider whether any of these applied:
- Recent IVIG infusion falsely elevates IgG (measure 3–6 months after last infusion for baseline)
- Rituximab therapy markedly suppresses IgG for 6–12 months
- Age-dependent normal ranges (IgG rises from birth to adulthood)
- Hemolysis may interfere with some nephelometry assays
Preparing for the test: No fasting required. Quantitative immunoglobulins (IgG, IgA, IgM) are measured by nephelometry or turbidimetry.
Symptoms That Often Prompt IgG Testing
- Recurrent sinopulmonary infections (sinusitis, pneumonia, bronchitis)
- Recurrent otitis media
- Unusually severe or prolonged infections
- In myeloma: bone pain, fatigue, anemia, kidney impairment
- Autoimmune manifestations in CVID (ITP, autoimmune hemolytic anemia)
Want the full clinical guide to Immunoglobulin G?
Reference ranges, causes, symptoms, preparation, and FAQs.