Transient Elastography in Healthy Children and Children with Cystic Fibrosis

Background: Transient Elastography (TE) is a point-of-care test, which has revolutionised the management of liver disease in adults and reduced the need for liver biopsy. TE has been used in a variety of liver diseases in children. However studies to evaluate its repeatability and reproducibility are limited. Aims to (i) evaluate the normal range, (ii) repeatability of TE in healthy children, (iii) determine if TE could facilitate early diagnosis and monitor disease progression in children with cystic fibrosis liver disease (CFLD). Methods: Healthy children had two measurements of liver stiffness to determine the upper limit of normal (ULN). The repeatability and reproducibility of TE was examined using Repeatability Coefficient (RC), Bland and Altman plots and Lin's Concordance Correlation Coefficient (CCC). 128 participants with CF, classified as (i) clinically significant liver disease (CSCFLD, n=20), (ii) nonspecific changes (NSCFLD, n=43) and (iii) no evidence of liver disease (NOCFLD, n=65), had TE measurements.   Findings: 235/257 (91·4%) volunteers had two valid measurements (mean age 11·7years, SD2·51, 45·3% male). The normal range of TE in healthy children was 2·88-6·52k Pa. The mean difference between paired measurements was -0.044 kPa, SD 0.414 with a normal distribution (Shapiro-Wilk test W= 0·99 p 1 kPa between measurements in 61/235 (25.9%) of healthy children. In CF, TE could distinguish children with advanced liver disease from those with no liver disease, but the repeatability of TE was also poor in CFLD. Interpretation: TE is not repeatable or reproducible in healthy children. This variability in TE performance indicates that TE does not have acceptable diagnostic accuracy in children. Funding Statement: This study was funded by the Health Research Board (HRA-POR-662) Declaration of Interests: None of the authors have any conflicts of interest to declare. Ethics Approval Statement: The study was approved by the Ethics Committees of Our Lady’s Children’s Hospital Crumlin (sports club volunteers and patients), The National Children’s Hospital, The Children’s University Hospital Temple Street, and St Vincent’s University Hospital Dublin. Signed consent to participate in the study was obtained from parents or guardians of both healthy volunteer children and CF participants.