The IgXSpot test is an enzyme–linked immunospot assay that detects human T cells reactive to Borrelia/pathogen–specific antigens in vitro. It is recommended for detection of very early and/or late Borrelia/pathogen infection and in seronegative patient’s whole blood samples. When combined with Lyme ImmunoBlot tests, this test provides information on the full spectrum of a patient’s immune response to infection and stage of disease. This test is unavailable for patients over 65 when ordered through physician services.