Clinical practices for intermediate sweat tests following abnormal cystic fibrosis newborn screens

Abstract

Background Newborn screening (NBS) for cystic fibrosis (CF) has become standard practice in many countries. Consequently, the prevalence of infants with intermediate/equivalent sweat test results has increased. This study examined clinical practices in the United States (US) related to intermediate sweat test results subsequent to NBS. Methods Telephone surveys were conducted with staff from 77 (47% response rate) US CF centers documenting clinical practices related to intermediate/equivalent sweat chloride levels (30–59 mmol/L) following abnormal NBS. Results Thirty percent of centers followed CF Foundation guidelines for classifying intermediate/equivalent results. There was much variability in sweat testing procedures, diagnostic labels, additional diagnostics, addressing prognosis, and services offered to parents. CF center staff identified a need for resources to better address the uncertainty associated with intermediate/equivalent results. Conclusion Findings warrant evaluation of barriers to adherence with existing guidelines and establishment of internationally accepted, evidenced-based, clinical standards for infants with intermediate/equivalent CF NBS results.

Cystic Fibrosis Screen Positive, Inconclusive Diagnosis (CFSPID): A new designation and management recommendations for infants with an inconclusive diagnosis following newborn screening

“…Despite these two guidelines, it has become apparent through published commentaries and surveys of European programmes that diverse practice exists with respect to the management of these infants, ranging from early discharge with little information to the family to full CF care in a CF centre [6,7]. There is limited data on the long-term outcomes, but it is clear from epidemiological studies that a significant number will have minimal or no phenotypic consequence [8,9].…”

Diagnosis of Cystic Fibrosis in Screened Populations

“…[11][12][13] Unclear diagnoses lead to treatment delays, persistent challenges, 14 and stress and confusion for both families 15,16 and clinicians. 17 This group of infants, with varying levels of symptoms and a variety of CFTR mutations, has been the focus of discussions in the US and in Europe, with somewhat differing conclusions on both diagnosis and management. 18,19 In addition, there has been a lack of international harmony regarding terminology, leading to confusion reflected in a recent article, entitled "Comparing the American and European diagnostic guidelines for cystic fibrosis: same disease, different language?"…”

Cystic Fibrosis Diagnostic Challenges over 4 Decades: Historical Perspectives and Lessons Learned

“…Although the vast majority of screened infants can be unequivocally diagnosed with CF after a positive newborn screen and sweat test, 9,10 the decision is not clearcut in a significant number of individuals, 11,12 leading to persistent challenges 13 and stress and confusion for both families 14,15 and clinicians. 16 This group, as well as symptomatic subjects identified without NBS who have varying levels of symptoms and a variety of CF transmembrane conductance regulator (CFTR) mutations, has been the focus of discussions in the US and in Europe, with differing conclusions on both diagnosis and management. 10,[17][18][19] In addition, there has been a lack of international harmony regarding terminology, leading to confusion.…”