TY - JOUR AU - Freij, Joudeh B AU - Secord, Elizabeth A PY - 2022 TI - Conditions Other than Severe Combined Immune Deficiency Found on SCID Newborn Screening JF - Medical Research Archives; Vol 10 No 8 (2022): VOl.10 Issue 8, AUGUST issue DO - 10.18103/mra.v10i8.3052 KW - N2 - Severe combined immune deficiency (SCID) is caused by a wide variety of genetic variants that result in absent or diminished levels of mature and functional T cells.  SCID Newborn Screening programs that detect T cell receptor excision circles have resulted in early intervention and improvement in survival rates in infants with SCID but have also identified other conditions with low T cells.  These conditions trigger what could be thought of as false positive tests for SCID, but for the most part they do reflect low T cells in conditions other than SCID. The scope of this review is entities other than severe combined immune deficiency that cause low T cell receptor excision circles (TRECs) and are thus identified on newborn screening.  Secondary immune deficiencies from prematurity, neonatal medical conditions, hypomorphic or incomplete variants of SCID, transient T cell lymphopenia of infancy, and primary immune deficiencies that do not qualify as SCID are all elaborated.   Identification and treatment options for these conditions leading to low TRECs are discussed. UR - https://esmed.org/MRA/mra/article/view/3052