Abstract
This article has defined in part the circumstances in which red cell cryptantigen exposure occurs and its significance in children. Bacteria-induced cryptantigens (T and Tk) are the most commonly encountered and, when present, suggest a guarded prognosis, a complicated clinical course, and a need for care in transfusion management with particular attention to the avoidance of plasma-containing products. Nonbacterial-induced cryptantigens (Th and Tn) are much less commonly seen and are encountered as a complicating feature of a serious hematologic condition and may be a potential source of confusion in the neonate.