Measurement of fecal elastase improves performance of newborn screening for cystic fibrosis

Juerg Barben; Corina S Rueegg; Maja Jurca; Johannes Spalinger; Claudia E Kuehni; Swiss Cystic Fibrosis Screening Group

doi:10.1016/j.jcf.2015.12.024

Measurement of fecal elastase improves performance of newborn screening for cystic fibrosis

J Cyst Fibros. 2016 May;15(3):313-7. doi: 10.1016/j.jcf.2015.12.024. Epub 2016 Jan 27.

Authors

Juerg Barben¹, Corina S Rueegg², Maja Jurca³, Johannes Spalinger⁴, Claudia E Kuehni³; Swiss Cystic Fibrosis Screening Group

Affiliations

¹ Division of Pediatric Pulmonology, Children's Hospital of Eastern Switzerland, St.Gallen, Switzerland. Electronic address: juerg.barben@kispisg.ch.
² Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland; Department of Health Sciences and Health Policy, University of Lucerne, Lucerne, Switzerland.
³ Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland.
⁴ Division of Pediatric Gastroenterology, Department of Paediatrics, Cantonal Hospital Lucerne, Switzerland.

PMID: 26826912
DOI: 10.1016/j.jcf.2015.12.024

Abstract

Background: The aim of newborn screening (NBS) for CF is to detect children with 'classic' CF where early treatment is possible and improves prognosis. Children with inconclusive CF diagnosis (CFSPID) should not be detected, as there is no evidence for improvement through early treatment. No algorithm in current NBS guidelines explains what to do when sweat test (ST) fails. This study compares the performance of three different algorithms for further diagnostic evaluations when first ST is unsuccessful, regarding the numbers of children detected with CF and CFSPID, and the time until a definite diagnosis.

Methods: In Switzerland, CF-NBS was introduced in January 2011 using an IRT-DNA-IRT algorithm followed by a ST. In children, in whom ST was not possible (no or insufficient sweat), 3 different protocols were applied between 2011 and 2014: in 2011, ST was repeated until it was successful (protocol A), in 2012 we proceeded directly to diagnostic DNA testing (protocol B), and 2013-2014, fecal elastase (FE) was measured in the stool, in order to determine a pancreas insufficiency needing immediate treatment (protocol C).

Results: The ratio CF:CFSPID was 7:1 (27/4) with protocol A, 2:1 (22/10) with protocol B, and 14:1 (54/4) with protocol C. The mean time to definite diagnosis was significantly shorter with protocol C (33days) compared to protocol A or B (42 and 40days; p=0.014 compared to A, and p=0.036 compared to B).

Conclusions: The algorithm for the diagnostic part of the newborn screening used in the CF centers is important and affects the performance of a CF-NBS program with regard to the ratio CF:CFSPID and the time until definite diagnosis. Our results suggest to include FE after initial sweat test failure in the CF-NBS guidelines to keep the proportion of CFSPID low and the time until definite diagnosis short.

Keywords: CFSPID; Cystic fibrosis; Fecal elastase; Newborn screening.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Algorithms
Clinical Protocols* / classification
Clinical Protocols* / standards
Cystic Fibrosis Transmembrane Conductance Regulator / genetics*
Cystic Fibrosis* / diagnosis
Cystic Fibrosis* / genetics
Cystic Fibrosis* / metabolism
Cystic Fibrosis* / therapy
Early Diagnosis
Early Medical Intervention / methods
Genetic Testing / methods
Humans
Infant, Newborn
Neonatal Screening / methods
Neonatal Screening / standards
Pancreatic Elastase / analysis*
Prognosis
Quality Improvement
Sweat / metabolism
Switzerland / epidemiology
Time Factors
Trypsinogen / analysis

Substances

Cystic Fibrosis Transmembrane Conductance Regulator
Trypsinogen
Pancreatic Elastase