The objective of the present study is to compare daily weight gain and laboratory analysis (72-hour fecal fat and steatocrit) with fecal elastase-1 (EL-1) when diagnosing pancreatic insufficiency (PI) in infants with cystic fibrosis (CF).
A total of 39 infants with CF, diagnosed consecutively by newborn screening at 2 referral centers, were included in the study. Daily weight gain and results of laboratory analysis of stool samples were compared using the κ coefficient and the receiver operator characteristic (ROC) curve.
Using the criterion of low daily weight gain, the frequency of PI was 92.3%; using the 72-hour fecal fat, steatocrit, and fecal EL-1 tests, the frequency was 42.3%, 86.2%, and 84.6%, respectively. EL-1 was used as the reference test. It was observed that the criteria of low daily weight gain (<50th percentile) and abnormal steatocrit, used together, showed the highest sensitivity (91.3%) and specificity (83.3%) for the diagnosis of PI.
When fecal EL-1 analysis is not immediately available, low daily weight gain associated with abnormal steatocrit can be adopted as a criterion for initiating pancreatic enzyme replacement therapy in infants with CF; however, EL-1 testing should be performed later for confirmation of PI.
*University Hospital/Federal University of Minas Gerais, Belo Horizonte
†Health Sciences Center, Federal University of Saõ João del-Rei, Divinópolis
‡Department of Pediatrics, Diagnostic Support Action and Research Center (NUPAD)/Medical School, Pediatric Gastroenterology Center/University Hospital–Federal University of Minas Gerais
§University Hospital, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Address correspondence and reprint requests to Elizabet V Guimarães, MD, PhD, Associate Professor, Departamento de Pediatria, Faculdade de Medicina da Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil (e-mail: firstname.lastname@example.org).
Received 26 October, 2011
Accepted 9 August, 2012
P.C. is supported by the Brazilian research agencies CNPq-Brazilian Council for Scientific and Technological Development (Grant #303827/2009-2) and FAPEMIG—Minas Gerais State Foundation for Research Support (Grant #PPM-00230-10).
The authors report no conflict of interest.