Inborn errors of immunity: phenotype-driven screen

Routes the immunodeficiency work-up by dominant phenotype, with the two highest-yield rules baked in: draw titers before Ig replacement, and exclude secondary causes first. Links the PPSV23-response calculator.

Evidence tier: Guideline-derived.

Decision points

  • Dominant phenotype?

Do-not-miss pitfalls

  • Do not start immunoglobulin replacement before drawing IgG and vaccine-specific titers, it masks the diagnosis for months.
  • Do not forget to exclude secondary causes (rituximab, protein loss, malignancy/CLL, thymoma/Good syndrome).
  • Do not give live vaccines when a severe T-cell defect is suspected; withhold pending TREC/flow.
  • Do not use adult immunoglobulin norms for children.
  • Do not diagnose IgG subclass deficiency without functional antibody context.

Evidence & citations

  1. Bonilla FA, Khan DA, Ballas ZK, et al. Practice parameter for the diagnosis and management of primary immunodeficiency. J Allergy Clin Immunol. 2015;136(5):1186-1205.e78. PMID 26371839
  2. Orange JS, Chinen J, Horner CC, et al. 2025 Inborn errors of immunity practice parameter (JTFPP/AAAAI/ACAAI/CIS). Ann Allergy Asthma Immunol. 2026;136(4):426-493.e1. PMID 41936423
  3. Bousfiha A, Moundir A, Tangye SG, et al. The 2024 update of IUIS phenotypic classification of human inborn errors of immunity. J Hum Immun. 2025. PMID 41608113

Clinician decision support. Verify against the cited source. Not a substitute for clinical judgment. 100% on-device; no patient data is stored or transmitted.