Immunodeficiency is when the pathways to remove pathogens is disrupted either by germline mutations (primary immunodeficiency), or secondary to infection (e.g. HIV), medication (e.g. B cell inhibitor rituximab), or malignancy
• History of frequent infections that is more than expected for a given age.
• If history is suggestive of an immunodeficiency, then you go on to ask more questions to determine what type of immunodeficiency they may have, and do laboratory tests to see if there is any abnormalities that may point to the type of immunodeficiency