Novel Testing Procedures

The purpose of this study is to evaluate a novel screening test to detect patients with primary immunodeficiencies(PIDs). The investigators plan to use information gained from this study in order to advance the field of clinical immunology, thus improving the diagnosis, treatment, and well-being of future patients. The purpose of this study is to determine if this screening test is able to detect patients with immune problems, and the investigators will test patients with known PIDs to determine if the test is accurate The investigators hypothesize that detecting serum immunoglobulins from dried blood spots will be effective in detecting patients with known primary immunodeficiencies. If our hypothesis is confirmed, it opens the possibility of using point of care testing to screen for primary immune deficiencies. Age of study subjects will range from 1 year to 80 years of age, and will be recruited form the Immunodeficiency clinic at the Medical College of Wisconsin/Children's Hospital of Wisconsin (MCW/CHW). Any subject having testing done to evaluate the immune system is eligible for this study. This will include patients with known PIDs as well as patients evaluated for a suspected immunodeficiency. It is anticipated that 150 subjects will be analyzed over a two year period.