Screening Newborns for Sickle Cell Anemia-Reply

In Reply.—Dr Smith would have preferred that our differential diagnosis of the proposita deal more extensively with β⁺ vs β° thalassemia and the difference in their clinical presentation. We point out that the differential diagnostic process for newborns differs from that appropriate for the symptomatic child in that there is no clinical history. The differential diagnosis is that of a hemoglobin composition, not that of a clinical course. The hemoglobin composition of the proposita described (principally Hb S without Hb A) automatically excludes sickle-β⁺ thalassemia, and therefore it was not discussed. As explained in the third paragraph of the "Comment" section, it is sickle-β thalassemia that must be distinguished from sickle cell anemia because in both there is no synthesis of Hb A.

Drs Grover and Wethers claim that, in the family described, "neither confirmatory testing nor family studies were obtained appropriately." Regarding confirmatory testing, as the article states,