[Diagnostics of immunodeficiencies]

This review finds that knowledge of primary immunodeficiencies (PID), also termed inborn errors of immunity (IEI), has expanded rapidly with advances in genetic and immunological methods. Precise diagnosis is crucial for targeted treatment in this patient group. Patients may present not only with infections but also with immune dysregulation such as autoimmunity, inflammation, or malignancy, occurring in both childhood and adulthood. Whole genome sequencing combined with functional immunological analyses has greatly improved diagnostics and guided therapy, leading to significantly better prognoses.