Neonatal Screening for Cystic Fibrosis: Position Paper

Abstract

Neonatal screening represents the search for a disorder in a general newborn population. The purpose of screening may be to improve the health of the affected infant, to provide counseling, or for research. Screening tests have been widely accepted for conditions such as phenylketonuria, hypothyroidism, and other metabolic conditions. Cystic fibrosis (CF) is the most common lethal genetic disorder among the white population (with a lower incidence among blacks), and thus there has been interest in screening newborns for CF¹ However, proposals emanating from this interest have remained controversial.^2-4 The recent development of a relatively simple test—the dried blood immuno-reactive trypsinogen (IRT) assay—has increased this interest.^5-12

Besides considering technical reliability and validity of newborn screening methods, it is crucial that all other aspects of screening (including medical, ethical, psychosocial, and economic aspects) be rigorously examined before implementing mass screening.^13-15 To address these issues the Cystic Fibrosis Foundation convened a Task Force on Neonatal Screening. Although the Task Force considered the current status of the IRT test, it focused on the generally accepted criteria for newborn screening, summarized in the Table,¹⁴ and the relationship of these criteria to the present state of knowledge related to CF. The issues identified by the Task Force, are summarized in this paper, and recommendations are presented at the conclusion.

EFFECTIVENESS OF PRESYMPTOMATIC TREATMENT

Evidence suggesting that the initiation of treatment before clinical manifestations of CF first appear improves prognosis has been controversial. Whereas some studies have yielded supportive data,¹⁶ others have not.⁴ There are no generally accepted treatment protocols for use in symptomatic or asymptomatic patients.