Agammaglobulinaemia and hypogammaglobulinaemia (CVID)
Working up a low IgG, excluding secondary causes, diagnosing CVID and XLA, testing vaccine responses before replacement, immunoglobulin dosing and trough targets under the NBA Criteria, and the non-infective complications of CVID.
Tier 1Condition
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- A low IgG is a sign, not a diagnosis. Secondary causes (drugs, haematological malignancy, protein loss) are far commoner in adults than primary antibody deficiency.
- CVID is the commonest symptomatic primary immunodeficiency in adults: low IgG plus low IgA and/or IgM, with poor vaccine responses, after secondary causes are excluded.
- X-linked agammaglobulinaemia (XLA) is a boy with absent B cells and absent immunoglobulins who becomes unwell after 6 months of age.
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Sources
- Primary Immunodeficiencies (PID) Clinical UpdateAU/NZASCIA (Australasian Society of Clinical Immunology and Allergy), 2025
- Position Statement: Immunoglobulin Replacement Therapy (IRT) for Primary Immunodeficiency (PID)AU/NZASCIA, 2025 (content updated May 2025)
- Criteria for the clinical use of immunoglobulin in Australia (Version 3; inborn errors of immunity with antibody deficiency, version 3.6, April 2025)AU/NZNational Blood Authority, Version 3; April 2025 update page, last updated 3 February 2026
- Human inborn errors of immunity: 2024 update on the classification from the International Union of Immunological Societies Expert Committee (Poli MC et al. J Hum Immun 2025;1(1):e20250003)International Union of Immunological Societies, 2024 update (published April 2025)
- The European Society for Immunodeficiencies (ESID) Registry Working Definitions for the Clinical Diagnosis of Inborn Errors of Immunity (Seidel MG et al. J Allergy Clin Immunol Pract 2019;7:1763-70)European Society for Immunodeficiencies, 2019
- International Consensus Document (ICON): Common Variable Immunodeficiency Disorders (Bonilla FA et al. J Allergy Clin Immunol Pract 2016;4:38-59)J Allergy Clin Immunol Pract, 2016
- Use and interpretation of diagnostic vaccination in primary immunodeficiency: a working group report of the AAAAI (Orange JS et al. J Allergy Clin Immunol 2012;130:S1-24)American Academy of Allergy, Asthma and Immunology, 2012
- Impact of trough IgG on pneumonia incidence in primary immunodeficiency: a meta-analysis of clinical studies (Orange JS et al. Clin Immunol 2010;137:21-30)Clinical Immunology, 2010
- British Lung Foundation/United Kingdom Primary Immunodeficiency Network consensus statement on the definition, diagnosis, and management of granulomatous-lymphocytic interstitial lung disease in CVID (Hurst JR et al. J Allergy Clin Immunol Pract 2017;5:938-45)J Allergy Clin Immunol Pract, 2017
- AusPAR: Joenja (leniolisib)AU/NZTherapeutic Goods Administration, Decision March 2025; AusPAR July 2025
- Last updated
- 14 November 2026
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