Diagnostic Studies - Diagnosis of Immunodeficiency Diseases

DIAGNOSTIC STUDIES

Investigation of an immunodeficiency is a step-by-step procedure in which tests are or-dered to confirm clinical impressions or the results of previous tests. The initial evalua-tion may involve simple assays such as a white blood cell count with leukocyte differen-tial, immunoglobulin assay, isohemagglutinin titers, lymphocyte subpopulation counts, an NBT test for phagocytic function, and a CH50 for complement activity. Depending on the results of this initial evaluation and on the clinical impression as to the nature of the immunodeficiency, further tests should be ordered so as to obtain the best possible defi-nition of the nature and degree of immunodeficiency. The purpose of the evaluation is twofold: to learn more about the human immune system and to classify the immunodefi-ciency into a major category, if possible, to allow a more rational approach to therapy and long term management.